diff --git a/Meta/CMake/locale_data.cmake b/Meta/CMake/locale_data.cmake
index 618f8ebed5c..9ef4b83f35d 100644
--- a/Meta/CMake/locale_data.cmake
+++ b/Meta/CMake/locale_data.cmake
@@ -75,7 +75,7 @@ if (ENABLE_UNICODE_DATABASE_DOWNLOAD)
         "${CLDR_VERSION_FILE}"
         "${LOCALE_DATA_HEADER}"
         "${LOCALE_DATA_IMPLEMENTATION}"
-        arguments -b "${CLDR_BCP47_PATH}" -r "${CLDR_CORE_PATH}" -l "${CLDR_LOCALES_PATH}" -m "${CLDR_MISC_PATH}" -n "${CLDR_NUMBERS_PATH}" -d "${CLDR_DATES_PATH}"
+        arguments -b "${CLDR_BCP47_PATH}" -r "${CLDR_CORE_PATH}" -m "${CLDR_MISC_PATH}" -n "${CLDR_NUMBERS_PATH}" -d "${CLDR_DATES_PATH}"
     )
     invoke_generator(
         "NumberFormatData"
diff --git a/Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateLocaleData.cpp b/Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateLocaleData.cpp
index 426816e8440..65e220a3c3e 100644
--- a/Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateLocaleData.cpp
+++ b/Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateLocaleData.cpp
@@ -33,38 +33,6 @@ static ByteString format_identifier(StringView owner, ByteString identifier)
     return identifier;
 }
 
-struct DisplayPattern {
-    unsigned hash() const
-    {
-        return pair_int_hash(locale_pattern, locale_separator);
-    }
-
-    bool operator==(DisplayPattern const& other) const
-    {
-        return (locale_pattern == other.locale_pattern)
-            && (locale_separator == other.locale_separator);
-    }
-
-    size_t locale_pattern { 0 };
-    size_t locale_separator { 0 };
-};
-
-template<>
-struct AK::Formatter<DisplayPattern> : Formatter<FormatString> {
-    ErrorOr<void> format(FormatBuilder& builder, DisplayPattern const& patterns)
-    {
-        return Formatter<FormatString>::format(builder,
-            "{{ {}, {} }}"sv,
-            patterns.locale_pattern,
-            patterns.locale_separator);
-    }
-};
-
-template<>
-struct AK::Traits<DisplayPattern> : public DefaultTraits<DisplayPattern> {
-    static unsigned hash(DisplayPattern const& p) { return p.hash(); }
-};
-
 struct ListPatterns {
     unsigned hash() const
     {
@@ -143,31 +111,10 @@ struct AK::Traits<TextLayout> : public DefaultTraits<TextLayout> {
     static unsigned hash(TextLayout const& t) { return t.hash(); }
 };
 
-using LanguageList = Vector<size_t>;
-using TerritoryList = Vector<size_t>;
-using ScriptList = Vector<size_t>;
-using CurrencyList = Vector<size_t>;
-using CalendarList = Vector<size_t>;
-using DateFieldList = Vector<size_t>;
 using KeywordList = Vector<size_t>;
 using ListPatternList = Vector<size_t>;
 
 struct LocaleData {
-    ByteString language;
-    Optional<ByteString> territory;
-    Optional<ByteString> variant;
-    size_t display_patterns { 0 };
-    size_t languages { 0 };
-    size_t territories { 0 };
-    size_t scripts { 0 };
-    size_t long_currencies { 0 };
-    size_t short_currencies { 0 };
-    size_t narrow_currencies { 0 };
-    size_t numeric_currencies { 0 };
-    size_t calendars { 0 };
-    size_t long_date_fields { 0 };
-    size_t short_date_fields { 0 };
-    size_t narrow_date_fields { 0 };
     size_t calendar_keywords { 0 };
     size_t collation_case_keywords { 0 };
     size_t collation_numeric_keywords { 0 };
@@ -183,13 +130,6 @@ struct LanguageMapping {
 
 struct CLDR {
     UniqueStringStorage unique_strings;
-    UniqueStorage<DisplayPattern> unique_display_patterns;
-    UniqueStorage<LanguageList> unique_language_lists;
-    UniqueStorage<TerritoryList> unique_territory_lists;
-    UniqueStorage<ScriptList> unique_script_lists;
-    UniqueStorage<CurrencyList> unique_currency_lists;
-    UniqueStorage<CalendarList> unique_calendar_lists;
-    UniqueStorage<DateFieldList> unique_date_field_lists;
     UniqueStorage<KeywordList> unique_keyword_lists;
     UniqueStorage<ListPatterns> unique_list_patterns;
     UniqueStorage<ListPatternList> unique_list_pattern_lists;
@@ -198,44 +138,12 @@ struct CLDR {
     HashMap<ByteString, LocaleData> locales;
     Vector<Alias> locale_aliases;
 
-    Vector<ByteString> languages;
-    HashMap<StringView, size_t> language_indices;
-
-    Vector<ByteString> territories;
-    HashMap<StringView, size_t> territory_indices;
-
-    Vector<ByteString> scripts;
-    HashMap<StringView, size_t> script_indices;
-
-    Vector<ByteString> variants;
-    HashMap<StringView, size_t> variant_indices;
-
-    Vector<ByteString> currencies;
-    HashMap<StringView, size_t> currency_indices;
-
-    Vector<ByteString> date_fields;
-    HashMap<StringView, size_t> date_fields_indices;
-
-    Vector<Alias> date_field_aliases {
-        // ECMA-402 and the CLDR refer to some date fields with different names. Defining these aliases
-        // means we can remain agnostic about the naming differences elsewhere.
-        { "dayperiod"sv, "dayPeriod"sv },
-        { "week"sv, "weekOfYear"sv },
-        { "zone"sv, "timeZoneName"sv },
-    };
-
     HashMap<ByteString, Vector<ByteString>> keywords;
     HashMap<ByteString, Vector<Alias>> keyword_aliases;
     HashMap<ByteString, ByteString> keyword_names;
 
     Vector<ByteString> list_pattern_types;
     Vector<ByteString> character_orders;
-    HashMap<ByteString, size_t> language_aliases;
-    HashMap<ByteString, size_t> territory_aliases;
-    HashMap<ByteString, size_t> script_aliases;
-    HashMap<ByteString, size_t> variant_aliases;
-    HashMap<ByteString, size_t> subdivision_aliases;
-    Vector<LanguageMapping> complex_mappings;
     Vector<LanguageMapping> likely_subtags;
     size_t max_variant_size { 0 };
 };
@@ -273,40 +181,6 @@ static ErrorOr<LanguageMapping> parse_language_mapping(CLDR& cldr, StringView ke
     return LanguageMapping { move(parsed_key), move(parsed_alias) };
 }
 
-static ErrorOr<void> parse_core_aliases(ByteString core_supplemental_path, CLDR& cldr)
-{
-    LexicalPath core_aliases_path(move(core_supplemental_path));
-    core_aliases_path = core_aliases_path.append("aliases.json"sv);
-
-    auto core_aliases = TRY(read_json_file(core_aliases_path.string()));
-    auto const& supplemental_object = core_aliases.as_object().get_object("supplemental"sv).value();
-    auto const& metadata_object = supplemental_object.get_object("metadata"sv).value();
-    auto const& alias_object = metadata_object.get_object("alias"sv).value();
-
-    auto append_aliases = [&](auto& alias_object, auto& alias_map) {
-        alias_object.for_each_member([&](auto const& key, JsonValue const& value) {
-            auto alias = value.as_object().get_byte_string("_replacement"sv).value();
-
-            if (key.contains('-')) {
-                auto mapping = TRY_OR_DISCARD(parse_language_mapping(cldr, key, alias));
-                cldr.max_variant_size = max(mapping.key.variants.size(), cldr.max_variant_size);
-                cldr.max_variant_size = max(mapping.alias.variants.size(), cldr.max_variant_size);
-                cldr.complex_mappings.append(move(mapping));
-            } else {
-                alias_map.set(key, cldr.unique_strings.ensure(alias));
-            }
-        });
-    };
-
-    append_aliases(alias_object.get_object("languageAlias"sv).value(), cldr.language_aliases);
-    append_aliases(alias_object.get_object("territoryAlias"sv).value(), cldr.territory_aliases);
-    append_aliases(alias_object.get_object("scriptAlias"sv).value(), cldr.script_aliases);
-    append_aliases(alias_object.get_object("variantAlias"sv).value(), cldr.variant_aliases);
-    append_aliases(alias_object.get_object("subdivisionAlias"sv).value(), cldr.subdivision_aliases);
-
-    return {};
-}
-
 static ErrorOr<void> parse_likely_subtags(ByteString core_supplemental_path, CLDR& cldr)
 {
     LexicalPath likely_subtags_path(move(core_supplemental_path));
@@ -326,149 +200,6 @@ static ErrorOr<void> parse_likely_subtags(ByteString core_supplemental_path, CLD
     return {};
 }
 
-static ErrorOr<void> parse_identity(ByteString locale_path, CLDR& cldr, LocaleData& locale)
-{
-    LexicalPath locale_display_names_path(move(locale_path)); // Note: Every JSON file defines identity data, so we can use any of them.
-    locale_display_names_path = locale_display_names_path.append("localeDisplayNames.json"sv);
-
-    auto const& locale_display_names = *TRY(read_json_file_with_cache(locale_display_names_path.string()));
-    auto const& main_object = locale_display_names.as_object().get_object("main"sv).value();
-    auto const& locale_object = main_object.get_object(locale_display_names_path.parent().basename()).value();
-    auto const& identity_object = locale_object.get_object("identity"sv).value();
-    auto const& language_string = identity_object.get_byte_string("language"sv).value();
-    auto const& territory_string = identity_object.get_byte_string("territory"sv);
-    auto const& script_string = identity_object.get_byte_string("script"sv);
-    auto const& variant_string = identity_object.get_byte_string("variant"sv);
-
-    locale.language = language_string;
-
-    if (territory_string.has_value()) {
-        locale.territory = territory_string.value();
-
-        if (!cldr.territory_indices.contains(*locale.territory)) {
-            cldr.territory_indices.set(*locale.territory, 0);
-            cldr.territories.append(*locale.territory);
-        }
-    }
-
-    if (script_string.has_value()) {
-        auto const& script = script_string.value();
-
-        if (!cldr.script_indices.contains(script)) {
-            cldr.script_indices.set(script, 0);
-            cldr.scripts.append(script);
-        }
-    }
-
-    if (variant_string.has_value()) {
-        locale.variant = variant_string.value();
-
-        if (!cldr.variant_indices.contains(*locale.variant)) {
-            cldr.variant_indices.set(*locale.variant, 0);
-            cldr.variants.append(*locale.variant);
-        }
-    }
-
-    return {};
-}
-
-static ErrorOr<void> parse_locale_display_patterns(ByteString locale_path, CLDR& cldr, LocaleData& locale)
-{
-    LexicalPath locale_display_names_path(move(locale_path));
-    locale_display_names_path = locale_display_names_path.append("localeDisplayNames.json"sv);
-
-    auto const& locale_display_names = *TRY(read_json_file_with_cache(locale_display_names_path.string()));
-    auto const& main_object = locale_display_names.as_object().get_object("main"sv).value();
-    auto const& locale_object = main_object.get_object(locale_display_names_path.parent().basename()).value();
-    auto const& locale_display_names_object = locale_object.get_object("localeDisplayNames"sv).value();
-    auto const& locale_display_patterns_object = locale_display_names_object.get_object("localeDisplayPattern"sv).value();
-    auto const& locale_pattern = locale_display_patterns_object.get_byte_string("localePattern"sv).value();
-    auto const& locale_separator = locale_display_patterns_object.get_byte_string("localeSeparator"sv).value();
-
-    DisplayPattern patterns {};
-    patterns.locale_pattern = cldr.unique_strings.ensure(locale_pattern);
-    patterns.locale_separator = cldr.unique_strings.ensure(locale_separator);
-
-    locale.display_patterns = cldr.unique_display_patterns.ensure(move(patterns));
-    return {};
-}
-
-static ErrorOr<void> preprocess_languages(ByteString locale_path, CLDR& cldr)
-{
-    LexicalPath languages_path(move(locale_path));
-    languages_path = languages_path.append("languages.json"sv);
-
-    if (!FileSystem::exists(languages_path.string()))
-        return {};
-
-    auto const& locale_languages = *TRY(read_json_file_with_cache(languages_path.string()));
-    auto const& main_object = locale_languages.as_object().get_object("main"sv).value();
-    auto const& locale_object = main_object.get_object(languages_path.parent().basename()).value();
-    auto const& locale_display_names_object = locale_object.get_object("localeDisplayNames"sv).value();
-    auto const& languages_object = locale_display_names_object.get_object("languages"sv).value();
-
-    languages_object.for_each_member([&](auto const& key, auto const&) {
-        if (!key.contains("-alt-"sv) && !cldr.language_indices.contains(key)) {
-            cldr.language_indices.set(key, 0);
-            cldr.languages.append(key);
-        }
-    });
-
-    return {};
-}
-
-static ErrorOr<void> preprocess_currencies(ByteString numbers_path, CLDR& cldr)
-{
-    LexicalPath currencies_path(move(numbers_path));
-    currencies_path = currencies_path.append("currencies.json"sv);
-
-    auto const& locale_currencies = *TRY(read_json_file_with_cache(currencies_path.string()));
-    auto const& main_object = locale_currencies.as_object().get_object("main"sv).value();
-    auto const& locale_object = main_object.get_object(currencies_path.parent().basename()).value();
-    auto const& locale_numbers_object = locale_object.get_object("numbers"sv).value();
-    auto const& currencies_object = locale_numbers_object.get_object("currencies"sv).value();
-
-    currencies_object.for_each_member([&](auto const& key, JsonValue const&) {
-        if (!cldr.currency_indices.contains(key)) {
-            cldr.currency_indices.set(key, 0);
-            cldr.currencies.append(key);
-        }
-    });
-
-    return {};
-}
-
-static bool is_sanctioned_date_field(StringView field)
-{
-    // This is a copy of the units sanctioned for use within ECMA-402, with names adjusted for the names used by the CLDR.
-    // https://tc39.es/ecma402/#table-validcodeforDateField
-    return field.is_one_of("era"sv, "year"sv, "quarter"sv, "month"sv, "week"sv, "weekday"sv, "day"sv, "dayperiod"sv, "hour"sv, "minute"sv, "second"sv, "zone"sv);
-}
-
-static ErrorOr<void> preprocess_date_fields(ByteString dates_path, CLDR& cldr)
-{
-    LexicalPath date_fields_path(move(dates_path));
-    date_fields_path = date_fields_path.append("dateFields.json"sv);
-
-    auto const& locale_date_fields = *TRY(read_json_file_with_cache(date_fields_path.string()));
-    auto const& main_object = locale_date_fields.as_object().get_object("main"sv).value();
-    auto const& locale_object = main_object.get_object(date_fields_path.parent().basename()).value();
-    auto const& dates_object = locale_object.get_object("dates"sv).value();
-    auto const& fields_object = dates_object.get_object("fields"sv).value();
-
-    fields_object.for_each_member([&](auto const& key, JsonValue const&) {
-        if (!is_sanctioned_date_field(key))
-            return;
-
-        if (!cldr.date_fields_indices.contains(key)) {
-            cldr.date_fields_indices.set(key, 0);
-            cldr.date_fields.append(key);
-        }
-    });
-
-    return {};
-}
-
 static ErrorOr<void> parse_unicode_extension_keywords(ByteString bcp47_path, CLDR& cldr)
 {
     constexpr auto desired_keywords = Array { "ca"sv, "co"sv, "hc"sv, "kf"sv, "kn"sv, "nu"sv };
@@ -533,102 +264,6 @@ static Optional<ByteString> find_keyword_alias(StringView key, StringView calend
     return alias->name;
 }
 
-static ErrorOr<void> parse_locale_languages(ByteString locale_path, CLDR& cldr, LocaleData& locale)
-{
-    LexicalPath languages_path(move(locale_path));
-    languages_path = languages_path.append("languages.json"sv);
-
-    LanguageList languages;
-    languages.resize(cldr.languages.size());
-
-    if (!FileSystem::exists(languages_path.string())) {
-        for (size_t i = 0; i < languages.size(); ++i)
-            languages[i] = cldr.unique_strings.ensure(cldr.languages[i]);
-
-        locale.languages = cldr.unique_language_lists.ensure(move(languages));
-        return {};
-    }
-
-    auto const& locale_languages = *TRY(read_json_file_with_cache(languages_path.string()));
-    auto const& main_object = locale_languages.as_object().get_object("main"sv).value();
-    auto const& locale_object = main_object.get_object(languages_path.parent().basename()).value();
-    auto const& locale_display_names_object = locale_object.get_object("localeDisplayNames"sv).value();
-    auto const& languages_object = locale_display_names_object.get_object("languages"sv).value();
-
-    languages_object.for_each_member([&](auto const& key, JsonValue const& value) {
-        if (key.contains("-alt-"sv))
-            return;
-
-        auto index = cldr.language_indices.get(key).value();
-        languages[index] = cldr.unique_strings.ensure(value.as_string());
-    });
-
-    locale.languages = cldr.unique_language_lists.ensure(move(languages));
-    return {};
-}
-
-static ErrorOr<void> parse_locale_territories(ByteString locale_path, CLDR& cldr, LocaleData& locale)
-{
-    LexicalPath territories_path(move(locale_path));
-    territories_path = territories_path.append("territories.json"sv);
-
-    TerritoryList territories;
-    territories.resize(cldr.territories.size());
-
-    if (!FileSystem::exists(territories_path.string())) {
-        for (size_t i = 0; i < territories.size(); ++i)
-            territories[i] = cldr.unique_strings.ensure(cldr.territories[i]);
-
-        locale.territories = cldr.unique_territory_lists.ensure(move(territories));
-        return {};
-    }
-
-    auto locale_territories = TRY(read_json_file(territories_path.string()));
-    auto const& main_object = locale_territories.as_object().get_object("main"sv).value();
-    auto const& locale_object = main_object.get_object(territories_path.parent().basename()).value();
-    auto const& locale_display_names_object = locale_object.get_object("localeDisplayNames"sv).value();
-    auto const& territories_object = locale_display_names_object.get_object("territories"sv).value();
-
-    territories_object.for_each_member([&](auto const& key, JsonValue const& value) {
-        if (auto index = cldr.territory_indices.get(key); index.has_value())
-            territories[*index] = cldr.unique_strings.ensure(value.as_string());
-    });
-
-    locale.territories = cldr.unique_territory_lists.ensure(move(territories));
-    return {};
-}
-
-static ErrorOr<void> parse_locale_scripts(ByteString locale_path, CLDR& cldr, LocaleData& locale)
-{
-    LexicalPath scripts_path(move(locale_path));
-    scripts_path = scripts_path.append("scripts.json"sv);
-
-    ScriptList scripts;
-    scripts.resize(cldr.scripts.size());
-
-    if (!FileSystem::exists(scripts_path.string())) {
-        for (size_t i = 0; i < scripts.size(); ++i)
-            scripts[i] = cldr.unique_strings.ensure(cldr.scripts[i]);
-
-        locale.scripts = cldr.unique_script_lists.ensure(move(scripts));
-        return {};
-    }
-
-    auto locale_scripts = TRY(read_json_file(scripts_path.string()));
-    auto const& main_object = locale_scripts.as_object().get_object("main"sv).value();
-    auto const& locale_object = main_object.get_object(scripts_path.parent().basename()).value();
-    auto const& locale_display_names_object = locale_object.get_object("localeDisplayNames"sv).value();
-    auto const& scripts_object = locale_display_names_object.get_object("scripts"sv).value();
-
-    scripts_object.for_each_member([&](auto const& key, JsonValue const& value) {
-        if (auto index = cldr.script_indices.get(key); index.has_value())
-            scripts[*index] = cldr.unique_strings.ensure(value.as_string());
-    });
-
-    locale.scripts = cldr.unique_script_lists.ensure(move(scripts));
-    return {};
-}
-
 static ErrorOr<void> parse_locale_list_patterns(ByteString misc_path, CLDR& cldr, LocaleData& locale)
 {
     LexicalPath list_patterns_path(move(misc_path));
@@ -711,124 +346,6 @@ static ErrorOr<void> parse_locale_layout(ByteString misc_path, CLDR& cldr, Local
     return {};
 }
 
-static ErrorOr<void> parse_locale_currencies(ByteString numbers_path, CLDR& cldr, LocaleData& locale)
-{
-    LexicalPath currencies_path(move(numbers_path));
-    currencies_path = currencies_path.append("currencies.json"sv);
-
-    auto const& locale_currencies = *TRY(read_json_file_with_cache(currencies_path.string()));
-    auto const& main_object = locale_currencies.as_object().get_object("main"sv).value();
-    auto const& locale_object = main_object.get_object(currencies_path.parent().basename()).value();
-    auto const& locale_numbers_object = locale_object.get_object("numbers"sv).value();
-    auto const& currencies_object = locale_numbers_object.get_object("currencies"sv).value();
-
-    CurrencyList long_currencies {};
-    long_currencies.resize(cldr.currencies.size());
-
-    CurrencyList short_currencies {};
-    short_currencies.resize(cldr.currencies.size());
-
-    CurrencyList narrow_currencies {};
-    narrow_currencies.resize(cldr.currencies.size());
-
-    CurrencyList numeric_currencies {};
-    numeric_currencies.resize(cldr.currencies.size());
-
-    currencies_object.for_each_member([&](auto const& key, JsonValue const& value) {
-        auto long_name = value.as_object().get_byte_string("displayName"sv).value_or(key);
-        auto short_name = value.as_object().get_byte_string("symbol"sv).value_or(key);
-        auto narrow_name = value.as_object().get_byte_string("symbol-alt-narrow"sv);
-        auto numeric_name = value.as_object().get_byte_string("displayName-count-other"sv);
-
-        auto index = cldr.currency_indices.get(key).value();
-        long_currencies[index] = cldr.unique_strings.ensure(move(long_name));
-        short_currencies[index] = cldr.unique_strings.ensure(move(short_name));
-        narrow_currencies[index] = narrow_name.has_value() ? cldr.unique_strings.ensure(narrow_name.release_value()) : 0;
-        numeric_currencies[index] = numeric_name.has_value() ? cldr.unique_strings.ensure(numeric_name.release_value()) : long_currencies[index];
-    });
-
-    locale.long_currencies = cldr.unique_currency_lists.ensure(move(long_currencies));
-    locale.short_currencies = cldr.unique_currency_lists.ensure(move(short_currencies));
-    locale.narrow_currencies = cldr.unique_currency_lists.ensure(move(narrow_currencies));
-    locale.numeric_currencies = cldr.unique_currency_lists.ensure(move(numeric_currencies));
-    return {};
-}
-
-static ErrorOr<void> parse_locale_calendars(ByteString locale_path, CLDR& cldr, LocaleData& locale)
-{
-    LexicalPath locale_display_names_path(move(locale_path));
-    locale_display_names_path = locale_display_names_path.append("localeDisplayNames.json"sv);
-
-    auto const& locale_display_names = *TRY(read_json_file_with_cache(locale_display_names_path.string()));
-    auto const& main_object = locale_display_names.as_object().get_object("main"sv).value();
-    auto const& locale_object = main_object.get_object(locale_display_names_path.parent().basename()).value();
-    auto const& locale_display_names_object = locale_object.get_object("localeDisplayNames"sv).value();
-
-    if (!locale_display_names_object.has_object("types"sv))
-        return {};
-
-    auto const& types_object = locale_display_names_object.get_object("types"sv).value();
-    auto const& calendar_object = types_object.get_object("calendar"sv).value();
-
-    auto const& supported_calendars = cldr.keywords.find("ca"sv)->value;
-
-    CalendarList calendars;
-    calendars.resize(supported_calendars.size());
-
-    calendar_object.for_each_member([&](auto const& key, auto const& calendar) {
-        auto index = supported_calendars.find_first_index(key);
-        if (!index.has_value()) {
-            auto alias = find_keyword_alias("ca"sv, key, cldr);
-            index = supported_calendars.find_first_index(*alias);
-        }
-
-        calendars[*index] = cldr.unique_strings.ensure(calendar.as_string());
-    });
-
-    locale.calendars = cldr.unique_calendar_lists.ensure(move(calendars));
-    return {};
-}
-
-static ErrorOr<void> parse_locale_date_fields(ByteString dates_path, CLDR& cldr, LocaleData& locale)
-{
-    LexicalPath date_fields_path(move(dates_path));
-    date_fields_path = date_fields_path.append("dateFields.json"sv);
-
-    auto const& locale_date_fields = *TRY(read_json_file_with_cache(date_fields_path.string()));
-    auto const& main_object = locale_date_fields.as_object().get_object("main"sv).value();
-    auto const& locale_object = main_object.get_object(date_fields_path.parent().basename()).value();
-    auto const& dates_object = locale_object.get_object("dates"sv).value();
-    auto const& fields_object = dates_object.get_object("fields"sv).value();
-
-    DateFieldList long_date_fields {};
-    long_date_fields.resize(cldr.date_fields.size());
-
-    DateFieldList short_date_fields {};
-    short_date_fields.resize(cldr.date_fields.size());
-
-    DateFieldList narrow_date_fields {};
-    narrow_date_fields.resize(cldr.date_fields.size());
-
-    fields_object.for_each_member([&](auto const& key, JsonValue const& value) {
-        if (!is_sanctioned_date_field(key))
-            return;
-
-        auto const& long_name = value.as_object().get_byte_string("displayName"sv).value();
-        auto const& short_name = fields_object.get_object(ByteString::formatted("{}-short", key))->get_byte_string("displayName"sv).value();
-        auto const& narrow_name = fields_object.get_object(ByteString::formatted("{}-narrow", key))->get_byte_string("displayName"sv).value();
-
-        auto index = cldr.date_fields_indices.get(key).value();
-        long_date_fields[index] = cldr.unique_strings.ensure(long_name);
-        short_date_fields[index] = cldr.unique_strings.ensure(short_name);
-        narrow_date_fields[index] = cldr.unique_strings.ensure(narrow_name);
-    });
-
-    locale.long_date_fields = cldr.unique_date_field_lists.ensure(move(long_date_fields));
-    locale.short_date_fields = cldr.unique_date_field_lists.ensure(move(short_date_fields));
-    locale.narrow_date_fields = cldr.unique_date_field_lists.ensure(move(narrow_date_fields));
-    return {};
-}
-
 static ErrorOr<void> parse_number_system_keywords(ByteString locale_numbers_path, CLDR& cldr, LocaleData& locale)
 {
     LexicalPath numbers_path(move(locale_numbers_path));
@@ -1008,13 +525,12 @@ static ErrorOr<void> define_aliases_without_scripts(CLDR& cldr)
     return {};
 }
 
-static ErrorOr<void> parse_all_locales(ByteString bcp47_path, ByteString core_path, ByteString locale_names_path, ByteString misc_path, ByteString numbers_path, ByteString dates_path, CLDR& cldr)
+static ErrorOr<void> parse_all_locales(ByteString bcp47_path, ByteString core_path, ByteString misc_path, ByteString numbers_path, ByteString dates_path, CLDR& cldr)
 {
     LexicalPath core_supplemental_path(core_path);
     core_supplemental_path = core_supplemental_path.append("supplemental"sv);
     VERIFY(FileSystem::is_directory(core_supplemental_path.string()));
 
-    TRY(parse_core_aliases(core_supplemental_path.string(), cldr));
     TRY(parse_likely_subtags(core_supplemental_path.string(), cldr));
 
     auto remove_variants_from_path = [&](ByteString path) -> ErrorOr<ByteString> {
@@ -1030,66 +546,12 @@ static ErrorOr<void> parse_all_locales(ByteString bcp47_path, ByteString core_pa
         return builder.to_byte_string();
     };
 
-    TRY(Core::Directory::for_each_entry(TRY(String::formatted("{}/main", locale_names_path)), Core::DirIterator::SkipParentAndBaseDir, [&](auto& entry, auto& directory) -> ErrorOr<IterationDecision> {
-        auto locale_path = LexicalPath::join(directory.path().string(), entry.name).string();
-        auto language = TRY(remove_variants_from_path(locale_path));
-
-        auto& locale = cldr.locales.ensure(language);
-        TRY(parse_identity(locale_path, cldr, locale));
-        return IterationDecision::Continue;
-    }));
-
-    TRY(Core::Directory::for_each_entry(TRY(String::formatted("{}/main", locale_names_path)), Core::DirIterator::SkipParentAndBaseDir, [&](auto& entry, auto& directory) -> ErrorOr<IterationDecision> {
-        auto locale_path = LexicalPath::join(directory.path().string(), entry.name).string();
-        TRY(preprocess_languages(locale_path, cldr));
-        return IterationDecision::Continue;
-    }));
-
-    TRY(Core::Directory::for_each_entry(TRY(String::formatted("{}/main", numbers_path)), Core::DirIterator::SkipParentAndBaseDir, [&](auto& entry, auto& directory) -> ErrorOr<IterationDecision> {
-        auto numbers_path = LexicalPath::join(directory.path().string(), entry.name).string();
-        TRY(preprocess_currencies(numbers_path, cldr));
-        return IterationDecision::Continue;
-    }));
-
-    TRY(Core::Directory::for_each_entry(TRY(String::formatted("{}/main", dates_path)), Core::DirIterator::SkipParentAndBaseDir, [&](auto& entry, auto& directory) -> ErrorOr<IterationDecision> {
-        auto dates_path = LexicalPath::join(directory.path().string(), entry.name).string();
-        TRY(preprocess_date_fields(dates_path, cldr));
-        return IterationDecision::Continue;
-    }));
-
-    auto update_indices = [](auto& keys, auto& indices) {
-        quick_sort(keys);
-
-        for (size_t i = 0; i < keys.size(); ++i)
-            indices.set(keys[i], i);
-    };
-
-    update_indices(cldr.languages, cldr.language_indices);
-    update_indices(cldr.territories, cldr.territory_indices);
-    update_indices(cldr.scripts, cldr.script_indices);
-    update_indices(cldr.variants, cldr.variant_indices);
-    update_indices(cldr.currencies, cldr.currency_indices);
-    update_indices(cldr.date_fields, cldr.date_fields_indices);
-
     TRY(Core::Directory::for_each_entry(TRY(String::formatted("{}/bcp47", bcp47_path)), Core::DirIterator::SkipParentAndBaseDir, [&](auto& entry, auto& directory) -> ErrorOr<IterationDecision> {
         auto bcp47_path = LexicalPath::join(directory.path().string(), entry.name).string();
         TRY(parse_unicode_extension_keywords(move(bcp47_path), cldr));
         return IterationDecision::Continue;
     }));
 
-    TRY(Core::Directory::for_each_entry(TRY(String::formatted("{}/main", locale_names_path)), Core::DirIterator::SkipParentAndBaseDir, [&](auto& entry, auto& directory) -> ErrorOr<IterationDecision> {
-        auto locale_path = LexicalPath::join(directory.path().string(), entry.name).string();
-        auto language = TRY(remove_variants_from_path(locale_path));
-
-        auto& locale = cldr.locales.ensure(language);
-        TRY(parse_locale_display_patterns(locale_path, cldr, locale));
-        TRY(parse_locale_languages(locale_path, cldr, locale));
-        TRY(parse_locale_territories(locale_path, cldr, locale));
-        TRY(parse_locale_scripts(locale_path, cldr, locale));
-        TRY(parse_locale_calendars(locale_path, cldr, locale));
-        return IterationDecision::Continue;
-    }));
-
     TRY(Core::Directory::for_each_entry(TRY(String::formatted("{}/main", misc_path)), Core::DirIterator::SkipParentAndBaseDir, [&](auto& entry, auto& directory) -> ErrorOr<IterationDecision> {
         auto misc_path = LexicalPath::join(directory.path().string(), entry.name).string();
         auto language = TRY(remove_variants_from_path(misc_path));
@@ -1105,7 +567,6 @@ static ErrorOr<void> parse_all_locales(ByteString bcp47_path, ByteString core_pa
         auto language = TRY(remove_variants_from_path(numbers_path));
 
         auto& locale = cldr.locales.ensure(language);
-        TRY(parse_locale_currencies(numbers_path, cldr, locale));
         TRY(parse_number_system_keywords(numbers_path, cldr, locale));
         fill_in_collation_keywords(cldr, locale);
         return IterationDecision::Continue;
@@ -1116,7 +577,6 @@ static ErrorOr<void> parse_all_locales(ByteString bcp47_path, ByteString core_pa
         auto language = TRY(remove_variants_from_path(dates_path));
 
         auto& locale = cldr.locales.ensure(language);
-        TRY(parse_locale_date_fields(dates_path, cldr, locale));
         TRY(parse_calendar_keywords(dates_path, cldr, locale));
         return IterationDecision::Continue;
     }));
@@ -1144,12 +604,6 @@ namespace Locale {
     auto keywords = cldr.keywords.keys();
 
     generate_enum(generator, format_identifier, "Locale"sv, "None"sv, locales, cldr.locale_aliases);
-    generate_enum(generator, format_identifier, "Language"sv, {}, cldr.languages);
-    generate_enum(generator, format_identifier, "Territory"sv, {}, cldr.territories);
-    generate_enum(generator, format_identifier, "ScriptTag"sv, {}, cldr.scripts);
-    generate_enum(generator, format_identifier, "Currency"sv, {}, cldr.currencies);
-    generate_enum(generator, format_identifier, "DateField"sv, {}, cldr.date_fields, cldr.date_field_aliases);
-    generate_enum(generator, format_identifier, "Variant"sv, {}, cldr.variants);
     generate_enum(generator, format_identifier, "ListPatternType"sv, {}, cldr.list_pattern_types);
     generate_enum(generator, format_identifier, "CharacterOrder"sv, {}, cldr.character_orders);
     generate_enum(generator, format_identifier, "Key"sv, {}, keywords);
@@ -1180,7 +634,6 @@ static ErrorOr<void> generate_unicode_locale_implementation(Core::InputBufferedF
     SourceGenerator generator { builder };
     generator.set("string_index_type"sv, string_index_type);
     generator.set("locales_size"sv, ByteString::number(cldr.locales.size()));
-    generator.set("territories_size", ByteString::number(cldr.territories.size()));
     generator.set("variants_size", ByteString::number(cldr.max_variant_size));
 
     generator.append(R"~~~(
@@ -1202,20 +655,6 @@ namespace Locale {
     cldr.unique_strings.generate(generator);
 
     generator.append(R"~~~(
-struct DisplayPatternImpl {
-    DisplayPattern to_display_pattern() const
-    {
-        DisplayPattern display_patterns {};
-        display_patterns.locale_pattern = decode_string(locale_pattern);
-        display_patterns.locale_separator = decode_string(locale_separator);
-
-        return display_patterns;
-    }
-
-    @string_index_type@ locale_pattern { 0 };
-    @string_index_type@ locale_separator { 0 };
-};
-
 struct Patterns {
     ListPatternType type;
     Style style;
@@ -1244,7 +683,6 @@ struct TextLayout {
         });
     generate_available_values(generator, "get_available_hour_cycles"sv, cldr.keywords.find("hc"sv)->value);
     generate_available_values(generator, "get_available_number_systems"sv, cldr.keywords.find("nu"sv)->value);
-    generate_available_values(generator, "get_available_currencies"sv, cldr.currencies);
 
     generator.append(R"~~~(
 ReadonlySpan<StringView> get_available_keyword_values(StringView key)
@@ -1272,13 +710,6 @@ ReadonlySpan<StringView> get_available_keyword_values(StringView key)
 }
 )~~~");
 
-    cldr.unique_display_patterns.generate(generator, "DisplayPatternImpl"sv, "s_display_patterns"sv, 30);
-    cldr.unique_language_lists.generate(generator, string_index_type, "s_language_lists"sv);
-    cldr.unique_territory_lists.generate(generator, string_index_type, "s_territory_lists"sv);
-    cldr.unique_script_lists.generate(generator, string_index_type, "s_script_lists"sv);
-    cldr.unique_currency_lists.generate(generator, string_index_type, "s_currency_lists"sv);
-    cldr.unique_calendar_lists.generate(generator, string_index_type, "s_calendar_lists"sv);
-    cldr.unique_date_field_lists.generate(generator, string_index_type, "s_date_field_lists"sv);
     cldr.unique_keyword_lists.generate(generator, string_index_type, "s_keyword_lists"sv);
     cldr.unique_list_patterns.generate(generator, "Patterns"sv, "s_list_patterns"sv, 10);
     cldr.unique_list_pattern_lists.generate(generator, cldr.unique_list_patterns.type_that_fits(), "s_list_pattern_lists"sv);
@@ -1328,18 +759,6 @@ static constexpr Array<@type@, @size@> @name@ { {)~~~");
     auto locales = cldr.locales.keys();
     quick_sort(locales);
 
-    append_mapping(locales, cldr.locales, cldr.unique_display_patterns.type_that_fits(), "s_locale_display_patterns"sv, [&](auto const& locale) { return locale.display_patterns; });
-    append_mapping(locales, cldr.locales, cldr.unique_language_lists.type_that_fits(), "s_languages"sv, [&](auto const& locale) { return locale.languages; });
-    append_mapping(locales, cldr.locales, cldr.unique_territory_lists.type_that_fits(), "s_territories"sv, [&](auto const& locale) { return locale.territories; });
-    append_mapping(locales, cldr.locales, cldr.unique_script_lists.type_that_fits(), "s_scripts"sv, [&](auto const& locale) { return locale.scripts; });
-    append_mapping(locales, cldr.locales, cldr.unique_currency_lists.type_that_fits(), "s_long_currencies"sv, [&](auto const& locale) { return locale.long_currencies; });
-    append_mapping(locales, cldr.locales, cldr.unique_currency_lists.type_that_fits(), "s_short_currencies"sv, [&](auto const& locale) { return locale.short_currencies; });
-    append_mapping(locales, cldr.locales, cldr.unique_currency_lists.type_that_fits(), "s_narrow_currencies"sv, [&](auto const& locale) { return locale.narrow_currencies; });
-    append_mapping(locales, cldr.locales, cldr.unique_currency_lists.type_that_fits(), "s_numeric_currencies"sv, [&](auto const& locale) { return locale.numeric_currencies; });
-    append_mapping(locales, cldr.locales, cldr.unique_calendar_lists.type_that_fits(), "s_calendars"sv, [&](auto const& locale) { return locale.calendars; });
-    append_mapping(locales, cldr.locales, cldr.unique_date_field_lists.type_that_fits(), "s_long_date_fields"sv, [&](auto const& locale) { return locale.long_date_fields; });
-    append_mapping(locales, cldr.locales, cldr.unique_date_field_lists.type_that_fits(), "s_short_date_fields"sv, [&](auto const& locale) { return locale.short_date_fields; });
-    append_mapping(locales, cldr.locales, cldr.unique_date_field_lists.type_that_fits(), "s_narrow_date_fields"sv, [&](auto const& locale) { return locale.narrow_date_fields; });
     append_mapping(locales, cldr.locales, cldr.unique_keyword_lists.type_that_fits(), "s_calendar_keywords"sv, [&](auto const& locale) { return locale.calendar_keywords; });
     append_mapping(locales, cldr.locales, cldr.unique_keyword_lists.type_that_fits(), "s_collation_case_keywords"sv, [&](auto const& locale) { return locale.collation_case_keywords; });
     append_mapping(locales, cldr.locales, cldr.unique_keyword_lists.type_that_fits(), "s_collation_numeric_keywords"sv, [&](auto const& locale) { return locale.collation_numeric_keywords; });
@@ -1351,42 +770,11 @@ static constexpr Array<@type@, @size@> @name@ { {)~~~");
 
 struct CanonicalLanguageID
 {
-    LanguageID to_unicode_language_id() const
-    {
-        LanguageID language_id {};
-        language_id.variants.ensure_capacity(variants_size);
-
-        language_id.language = MUST(String::from_utf8(decode_string(language)));
-        if (script != 0)
-            language_id.script = MUST(String::from_utf8(decode_string(script)));
-        if (region != 0)
-            language_id.region = MUST(String::from_utf8(decode_string(region)));
-        for (size_t i = 0; i < variants_size; ++i)
-            language_id.variants.append(MUST(String::from_utf8(decode_string(variants[i]))));
-
-        return language_id;
-    }
-
-    bool matches_variants(Vector<String> const& other_variants) const {
-        if (variants_size == 0)
-            return true;
-        if (other_variants.size() != variants_size)
-            return false;
-
-        for (size_t i = 0; i < variants_size; ++i) {
-            if (decode_string(variants[i]) != other_variants[i])
-                return false;
-        }
-
-        return true;
-    };
-
     @string_index_type@ language { 0 };
     @string_index_type@ script { 0 };
     @string_index_type@ region { 0 };
     Array<@string_index_type@, @variants_size@> variants {};
     size_t variants_size { 0 };
-
 };
 
 struct LanguageMapping {
@@ -1436,7 +824,6 @@ static constexpr Array<LanguageMapping, @size@> s_@name@ { {
         generator.append("} };\n");
     };
 
-    append_complex_mapping("complex_alias"sv, cldr.complex_mappings);
     append_complex_mapping("likely_subtags"sv, cldr.likely_subtags);
 
     generator.append(R"~~~(
@@ -1529,39 +916,6 @@ static LanguageMapping const* resolve_likely_subtag(LanguageID const& language_i
 
 )~~~");
 
-    auto append_mapping_search = [&](StringView enum_snake, StringView from_string_name, StringView collection_name, StringView unique_list) {
-        generator.set("enum_snake", enum_snake);
-        generator.set("from_string_name", from_string_name);
-        generator.set("collection_name", collection_name);
-        generator.set("unique_list", unique_list);
-
-        generator.append(R"~~~(
-Optional<StringView> get_locale_@enum_snake@_mapping(StringView locale, StringView @enum_snake@)
-{
-    auto locale_value = locale_from_string(locale);
-    if (!locale_value.has_value())
-        return {};
-
-    auto @enum_snake@_value = @from_string_name@_from_string(@enum_snake@);
-    if (!@enum_snake@_value.has_value())
-        return {};
-
-    auto locale_index = to_underlying(*locale_value) - 1; // Subtract 1 because 0 == Locale::None.
-    auto @enum_snake@_index = to_underlying(*@enum_snake@_value);
-
-    auto mapping_index = @collection_name@.at(locale_index);
-    auto const& mappings = @unique_list@.at(mapping_index);
-
-    auto @enum_snake@_string_index = mappings.at(@enum_snake@_index);
-    auto @enum_snake@_mapping = decode_string(@enum_snake@_string_index);
-
-    if (@enum_snake@_mapping.is_empty())
-        return {};
-    return @enum_snake@_mapping;
-}
-)~~~");
-    };
-
     auto append_from_string = [&](StringView enum_title, StringView enum_snake, auto const& values, Vector<Alias> const& aliases = {}) -> ErrorOr<void> {
         HashValueMap<ByteString> hashes;
         TRY(hashes.try_ensure_capacity(values.size()));
@@ -1576,47 +930,7 @@ Optional<StringView> get_locale_@enum_snake@_mapping(StringView locale, StringVi
         return {};
     };
 
-    auto append_alias_search = [&](StringView enum_snake, auto const& aliases) -> ErrorOr<void> {
-        HashValueMap<size_t> hashes;
-        TRY(hashes.try_ensure_capacity(aliases.size()));
-
-        for (auto const& alias : aliases)
-            hashes.set(alias.key.hash(), alias.value);
-
-        ValueFromStringOptions options {};
-        options.return_type = "StringView"sv;
-        options.return_format = "decode_string({})"sv;
-
-        generate_value_from_string(generator, "resolve_{}_alias"sv, string_index_type, enum_snake, move(hashes), options);
-
-        return {};
-    };
-
     TRY(append_from_string("Locale"sv, "locale"sv, cldr.locales.keys(), cldr.locale_aliases));
-
-    TRY(append_from_string("Language"sv, "language"sv, cldr.languages));
-    append_mapping_search("language"sv, "language"sv, "s_languages"sv, "s_language_lists"sv);
-    TRY(append_alias_search("language"sv, cldr.language_aliases));
-
-    TRY(append_from_string("Territory"sv, "territory"sv, cldr.territories));
-    append_mapping_search("territory"sv, "territory"sv, "s_territories"sv, "s_territory_lists"sv);
-    TRY(append_alias_search("territory"sv, cldr.territory_aliases));
-
-    TRY(append_from_string("ScriptTag"sv, "script_tag"sv, cldr.scripts));
-    append_mapping_search("script"sv, "script_tag"sv, "s_scripts"sv, "s_script_lists"sv);
-    TRY(append_alias_search("script_tag"sv, cldr.script_aliases));
-
-    TRY(append_from_string("Currency"sv, "currency"sv, cldr.currencies));
-    append_mapping_search("long_currency"sv, "currency"sv, "s_long_currencies"sv, "s_currency_lists"sv);
-    append_mapping_search("short_currency"sv, "currency"sv, "s_short_currencies"sv, "s_currency_lists"sv);
-    append_mapping_search("narrow_currency"sv, "currency"sv, "s_narrow_currencies"sv, "s_currency_lists"sv);
-    append_mapping_search("numeric_currency"sv, "currency"sv, "s_numeric_currencies"sv, "s_currency_lists"sv);
-
-    TRY(append_from_string("DateField"sv, "date_field"sv, cldr.date_fields, cldr.date_field_aliases));
-    append_mapping_search("long_date_field"sv, "date_field"sv, "s_long_date_fields"sv, "s_date_field_lists"sv);
-    append_mapping_search("short_date_field"sv, "date_field"sv, "s_short_date_fields"sv, "s_date_field_lists"sv);
-    append_mapping_search("narrow_date_field"sv, "date_field"sv, "s_narrow_date_fields"sv, "s_date_field_lists"sv);
-
     TRY(append_from_string("Key"sv, "key"sv, cldr.keywords.keys()));
 
     for (auto const& keyword : cldr.keywords) {
@@ -1630,11 +944,6 @@ Optional<StringView> get_locale_@enum_snake@_mapping(StringView locale, StringVi
             TRY(append_from_string(enum_name, enum_snake, keyword.value));
     }
 
-    append_mapping_search("calendar"sv, "keyword_ca"sv, "s_calendars"sv, "s_calendar_lists"sv);
-
-    TRY(append_alias_search("variant"sv, cldr.variant_aliases));
-    TRY(append_alias_search("subdivision"sv, cldr.subdivision_aliases));
-
     TRY(append_from_string("ListPatternType"sv, "list_pattern_type"sv, cldr.list_pattern_types));
 
     TRY(append_from_string("CharacterOrder"sv, "character_order"sv, cldr.character_orders));
@@ -1735,19 +1044,6 @@ Vector<StringView> get_keywords_for_locale(StringView locale, StringView key)
     return keywords;
 }
 
-Optional<DisplayPattern> get_locale_display_patterns(StringView locale)
-{
-    auto locale_value = locale_from_string(locale);
-    if (!locale_value.has_value())
-        return {};
-
-    auto locale_index = to_underlying(*locale_value) - 1; // Subtract 1 because 0 == Locale::None.
-    auto display_patterns_index = s_locale_display_patterns.at(locale_index);
-
-    auto const& display_patterns = s_display_patterns.at(display_patterns_index);
-    return display_patterns.to_display_pattern();
-}
-
 Optional<ListPatterns> get_locale_list_patterns(StringView locale, StringView list_pattern_type, Style list_pattern_style)
 {
     auto locale_value = locale_from_string(locale);
@@ -1798,37 +1094,6 @@ Optional<CharacterOrder> character_order_for_locale(StringView locale)
     return {};
 }
 
-void resolve_complex_language_aliases(LanguageID& language_id)
-{
-    for (auto const& map : s_complex_alias) {
-        auto key_language = decode_string(map.key.language);
-        auto key_script = decode_string(map.key.script);
-        auto key_region  = decode_string(map.key.region);
-
-        if ((key_language != language_id.language) && (key_language != "und"sv))
-            continue;
-        if (!key_script.is_empty() && (key_script != language_id.script))
-            continue;
-        if (!key_region.is_empty() && (key_region != language_id.region))
-            continue;
-        if (!map.key.matches_variants(language_id.variants))
-            continue;
-
-        auto alias = map.alias.to_unicode_language_id();
-
-        if (alias.language == "und"sv)
-            alias.language = move(language_id.language);
-        if (key_script.is_empty() && !alias.script.has_value())
-            alias.script = move(language_id.script);
-        if (key_region.is_empty() && !alias.region.has_value())
-            alias.region = move(language_id.region);
-        if (map.key.variants_size == 0 && alias.variants.is_empty())
-            alias.variants = move(language_id.variants);
-
-        language_id = move(alias);
-        break;
-    }
-}
 
 Optional<LanguageID> add_likely_subtags(LanguageID const& language_id)
 {
@@ -1856,13 +1121,6 @@ Optional<LanguageID> add_likely_subtags(LanguageID const& language_id)
     return maximized;
 }
 
-Optional<String> resolve_most_likely_territory(LanguageID const& language_id)
-{
-    if (auto const* likely_subtag = resolve_likely_subtag(language_id); likely_subtag != nullptr)
-        return MUST(String::from_utf8(decode_string(likely_subtag->alias.region)));
-    return OptionalNone {};
-}
-
 }
 )~~~");
 
@@ -1876,7 +1134,6 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     StringView generated_implementation_path;
     StringView bcp47_path;
     StringView core_path;
-    StringView locale_names_path;
     StringView misc_path;
     StringView numbers_path;
     StringView dates_path;
@@ -1886,7 +1143,6 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     args_parser.add_option(generated_implementation_path, "Path to the Unicode locale implementation file to generate", "generated-implementation-path", 'c', "generated-implementation-path");
     args_parser.add_option(bcp47_path, "Path to cldr-bcp47 directory", "bcp47-path", 'b', "bcp47-path");
     args_parser.add_option(core_path, "Path to cldr-core directory", "core-path", 'r', "core-path");
-    args_parser.add_option(locale_names_path, "Path to cldr-localenames directory", "locale-names-path", 'l', "locale-names-path");
     args_parser.add_option(misc_path, "Path to cldr-misc directory", "misc-path", 'm', "misc-path");
     args_parser.add_option(numbers_path, "Path to cldr-numbers directory", "numbers-path", 'n', "numbers-path");
     args_parser.add_option(dates_path, "Path to cldr-dates directory", "dates-path", 'd', "dates-path");
@@ -1896,7 +1152,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     auto generated_implementation_file = TRY(open_file(generated_implementation_path, Core::File::OpenMode::Write));
 
     CLDR cldr;
-    TRY(parse_all_locales(bcp47_path, core_path, locale_names_path, misc_path, numbers_path, dates_path, cldr));
+    TRY(parse_all_locales(bcp47_path, core_path, misc_path, numbers_path, dates_path, cldr));
 
     TRY(generate_unicode_locale_header(*generated_header_file, cldr));
     TRY(generate_unicode_locale_implementation(*generated_implementation_file, cldr));
diff --git a/Tests/LibLocale/CMakeLists.txt b/Tests/LibLocale/CMakeLists.txt
index a2b44e84dd6..e31bf262b4e 100644
--- a/Tests/LibLocale/CMakeLists.txt
+++ b/Tests/LibLocale/CMakeLists.txt
@@ -1,5 +1,6 @@
 set(TEST_SOURCES
     TestDateTimeFormat.cpp
+    TestDisplayNames.cpp
     TestLocale.cpp
 )
 
diff --git a/Tests/LibLocale/TestDisplayNames.cpp b/Tests/LibLocale/TestDisplayNames.cpp
new file mode 100644
index 00000000000..44df60557df
--- /dev/null
+++ b/Tests/LibLocale/TestDisplayNames.cpp
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2021, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibTest/TestCase.h>
+
+#include <LibLocale/DisplayNames.h>
+#include <LibLocale/Locale.h>
+
+TEST_CASE(locale_mappings_en)
+{
+    auto language = Locale::language_display_name("en"sv, "en"sv, Locale::LanguageDisplay::Standard);
+    EXPECT(language.has_value());
+    EXPECT_EQ(*language, "English"sv);
+
+    language = Locale::language_display_name("en"sv, "i-defintely-don't-exist"sv, Locale::LanguageDisplay::Standard);
+    EXPECT(!language.has_value());
+
+    auto territory = Locale::region_display_name("en"sv, "US"sv);
+    EXPECT(territory.has_value());
+    EXPECT_EQ(*territory, "United States"sv);
+
+    territory = Locale::region_display_name("en"sv, "i-defintely-don't-exist"sv);
+    EXPECT(!territory.has_value());
+
+    auto script = Locale::script_display_name("en"sv, "Latn"sv);
+    EXPECT(script.has_value());
+    EXPECT_EQ(*script, "Latin"sv);
+
+    script = Locale::script_display_name("en"sv, "i-defintely-don't-exist"sv);
+    EXPECT(!script.has_value());
+}
+
+TEST_CASE(locale_mappings_fr)
+{
+    auto language = Locale::language_display_name("fr"sv, "en"sv, Locale::LanguageDisplay::Standard);
+    EXPECT(language.has_value());
+    EXPECT_EQ(*language, "anglais"sv);
+
+    language = Locale::language_display_name("fr"sv, "i-defintely-don't-exist"sv, Locale::LanguageDisplay::Standard);
+    EXPECT(!language.has_value());
+
+    auto territory = Locale::region_display_name("fr"sv, "US"sv);
+    EXPECT(territory.has_value());
+    EXPECT_EQ(*territory, "États-Unis"sv);
+
+    territory = Locale::region_display_name("fr"sv, "i-defintely-don't-exist"sv);
+    EXPECT(!territory.has_value());
+
+    auto script = Locale::script_display_name("fr"sv, "Latn"sv);
+    EXPECT(script.has_value());
+    EXPECT_EQ(*script, "latin"sv);
+
+    script = Locale::script_display_name("fr"sv, "i-defintely-don't-exist"sv);
+    EXPECT(!script.has_value());
+}
+
+TEST_CASE(locale_mappings_root)
+{
+    auto language = Locale::language_display_name("und"sv, "en"sv, Locale::LanguageDisplay::Standard);
+    EXPECT(language.has_value());
+    EXPECT_EQ(*language, "en"sv);
+
+    language = Locale::language_display_name("und"sv, "i-defintely-don't-exist"sv, Locale::LanguageDisplay::Standard);
+    EXPECT(!language.has_value());
+
+    auto territory = Locale::region_display_name("und"sv, "US"sv);
+    EXPECT(territory.has_value());
+    EXPECT_EQ(*territory, "US"sv);
+
+    territory = Locale::region_display_name("und"sv, "i-defintely-don't-exist"sv);
+    EXPECT(!territory.has_value());
+
+    auto script = Locale::script_display_name("und"sv, "Latn"sv);
+    EXPECT(script.has_value());
+    EXPECT_EQ(*script, "Latn"sv);
+
+    script = Locale::script_display_name("und"sv, "i-defintely-don't-exist"sv);
+    EXPECT(!script.has_value());
+}
diff --git a/Tests/LibLocale/TestLocale.cpp b/Tests/LibLocale/TestLocale.cpp
index 76458868648..022c47b2198 100644
--- a/Tests/LibLocale/TestLocale.cpp
+++ b/Tests/LibLocale/TestLocale.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2021-2024, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -338,11 +338,8 @@ TEST_CASE(parse_unicode_locale_id_with_private_use_extension)
 TEST_CASE(canonicalize_unicode_locale_id)
 {
     auto test = [](StringView locale, StringView expected_canonical_locale) {
-        auto locale_id = Locale::parse_unicode_locale_id(locale);
-        VERIFY(locale_id.has_value());
-
-        auto canonical_locale = Locale::canonicalize_unicode_locale_id(*locale_id);
-        EXPECT_EQ(*canonical_locale, expected_canonical_locale);
+        auto canonical_locale = Locale::canonicalize_unicode_locale_id(locale);
+        EXPECT_EQ(canonical_locale, expected_canonical_locale);
     };
 
     test("aaa"sv, "aaa"sv);
@@ -373,8 +370,8 @@ TEST_CASE(canonicalize_unicode_locale_id)
     test("EN-U-KB-YES"sv, "en-u-kb"sv);
     test("en-u-kb-yes-abcd"sv, "en-u-kb-yes-abcd"sv);
     test("EN-U-KB-YES-ABCD"sv, "en-u-kb-yes-abcd"sv);
-    test("en-u-ka-yes"sv, "en-u-ka-yes"sv);
-    test("EN-U-KA-YES"sv, "en-u-ka-yes"sv);
+    test("en-u-ka-yes"sv, "en-u-ka"sv);
+    test("EN-U-KA-YES"sv, "en-u-ka"sv);
     test("en-u-1k-names"sv, "en-u-1k-names"sv);
     test("EN-U-1K-NAMES"sv, "en-u-1k-names"sv);
     test("en-u-ks-primary"sv, "en-u-ks-level1"sv);
@@ -518,75 +515,3 @@ TEST_CASE(supports_locale_aliases)
     EXPECT(Locale::is_locale_available("zh-TW"sv));
     EXPECT(Locale::is_locale_available("zh-Hant-TW"sv));
 }
-
-TEST_CASE(locale_mappings_en)
-{
-    auto language = Locale::get_locale_language_mapping("en"sv, "en"sv);
-    EXPECT(language.has_value());
-    EXPECT_EQ(*language, "English"sv);
-
-    language = Locale::get_locale_language_mapping("en"sv, "i-defintely-don't-exist"sv);
-    EXPECT(!language.has_value());
-
-    auto territory = Locale::get_locale_territory_mapping("en"sv, "US"sv);
-    EXPECT(territory.has_value());
-    EXPECT_EQ(*territory, "United States"sv);
-
-    territory = Locale::get_locale_territory_mapping("en"sv, "i-defintely-don't-exist"sv);
-    EXPECT(!territory.has_value());
-
-    auto script = Locale::get_locale_script_mapping("en"sv, "Latn"sv);
-    EXPECT(script.has_value());
-    EXPECT_EQ(*script, "Latin"sv);
-
-    script = Locale::get_locale_script_mapping("en"sv, "i-defintely-don't-exist"sv);
-    EXPECT(!script.has_value());
-}
-
-TEST_CASE(locale_mappings_fr)
-{
-    auto language = Locale::get_locale_language_mapping("fr"sv, "en"sv);
-    EXPECT(language.has_value());
-    EXPECT_EQ(*language, "anglais"sv);
-
-    language = Locale::get_locale_language_mapping("fr"sv, "i-defintely-don't-exist"sv);
-    EXPECT(!language.has_value());
-
-    auto territory = Locale::get_locale_territory_mapping("fr"sv, "US"sv);
-    EXPECT(territory.has_value());
-    EXPECT_EQ(*territory, "États-Unis"sv);
-
-    territory = Locale::get_locale_territory_mapping("fr"sv, "i-defintely-don't-exist"sv);
-    EXPECT(!territory.has_value());
-
-    auto script = Locale::get_locale_script_mapping("fr"sv, "Latn"sv);
-    EXPECT(script.has_value());
-    EXPECT_EQ(*script, "latin"sv);
-
-    script = Locale::get_locale_script_mapping("fr"sv, "i-defintely-don't-exist"sv);
-    EXPECT(!script.has_value());
-}
-
-TEST_CASE(locale_mappings_root)
-{
-    auto language = Locale::get_locale_language_mapping("und"sv, "en"sv);
-    EXPECT(language.has_value());
-    EXPECT_EQ(*language, "en"sv);
-
-    language = Locale::get_locale_language_mapping("und"sv, "i-defintely-don't-exist"sv);
-    EXPECT(!language.has_value());
-
-    auto territory = Locale::get_locale_territory_mapping("und"sv, "US"sv);
-    EXPECT(territory.has_value());
-    EXPECT_EQ(*territory, "US"sv);
-
-    territory = Locale::get_locale_territory_mapping("und"sv, "i-defintely-don't-exist"sv);
-    EXPECT(!territory.has_value());
-
-    auto script = Locale::get_locale_script_mapping("und"sv, "Latn"sv);
-    EXPECT(script.has_value());
-    EXPECT_EQ(*script, "Latn"sv);
-
-    script = Locale::get_locale_script_mapping("und"sv, "i-defintely-don't-exist"sv);
-    EXPECT(!script.has_value());
-}
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/AbstractOperations.cpp b/Userland/Libraries/LibJS/Runtime/Intl/AbstractOperations.cpp
index 20af3aac1bd..931963d3f7e 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/AbstractOperations.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/AbstractOperations.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2023, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2021-2024, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -21,7 +21,7 @@
 namespace JS::Intl {
 
 // 6.2.2 IsStructurallyValidLanguageTag ( locale ), https://tc39.es/ecma402/#sec-isstructurallyvalidlanguagetag
-Optional<::Locale::LocaleID> is_structurally_valid_language_tag(StringView locale)
+bool is_structurally_valid_language_tag(StringView locale)
 {
     auto contains_duplicate_variant = [&](auto& variants) {
         if (variants.is_empty())
@@ -37,90 +37,78 @@ Optional<::Locale::LocaleID> is_structurally_valid_language_tag(StringView local
         return false;
     };
 
-    // IsStructurallyValidLanguageTag returns true if all of the following conditions hold, false otherwise:
+    // 1. Let lowerLocale be the ASCII-lowercase of locale.
+    // NOTE: LibLocale's parsing is case-insensitive.
 
-    // locale can be generated from the EBNF grammar for unicode_locale_id in Unicode Technical Standard #35 LDML § 3.2 Unicode Locale Identifier;
+    // 2. If lowerLocale cannot be matched by the unicode_locale_id Unicode locale nonterminal, return false.
     auto locale_id = ::Locale::parse_unicode_locale_id(locale);
     if (!locale_id.has_value())
-        return {};
+        return false;
 
-    // locale does not use any of the backwards compatibility syntax described in Unicode Technical Standard #35 LDML § 3.3 BCP 47 Conformance;
-    // https://unicode.org/reports/tr35/#BCP_47_Conformance
+    // 3. If lowerLocale uses any of the backwards compatibility syntax described in Unicode Technical Standard #35 Part 1 Core,
+    //    Section 3.3 BCP 47 Conformance, return false.
+    //    https://unicode.org/reports/tr35/#BCP_47_Conformance
     if (locale.contains('_') || locale_id->language_id.is_root || !locale_id->language_id.language.has_value())
-        return {};
+        return false;
 
-    // the unicode_language_id within locale contains no duplicate unicode_variant_subtag subtags; and
-    if (contains_duplicate_variant(locale_id->language_id.variants))
-        return {};
+    // 4. Let languageId be the longest prefix of lowerLocale matched by the unicode_language_id Unicode locale nonterminal.
+    auto& language_id = locale_id->language_id;
 
-    // if locale contains an extensions* component, that component
-    Vector<char> unique_keys;
+    // 5. Let variants be GetLocaleVariants(languageId).
+    // 6. If variants is not undefined, then
+    if (auto& variants = language_id.variants; !variants.is_empty()) {
+        // a. If variants contains any duplicate subtags, return false.
+        if (contains_duplicate_variant(variants))
+            return false;
+    }
+
+    HashTable<char> unique_keys;
+
+    // 7. Let allExtensions be the suffix of lowerLocale following languageId.
+    // 8. If allExtensions contains a substring matched by the pu_extensions Unicode locale nonterminal, let extensions be
+    //    the prefix of allExtensions preceding the longest such substring. Otherwise, let extensions be allExtensions.
+    // 9. If extensions is not the empty String, then
     for (auto& extension : locale_id->extensions) {
-        // does not contain any other_extensions components with duplicate [alphanum-[tTuUxX]] subtags,
-        // contains at most one unicode_locale_extensions component,
-        // contains at most one transformed_extensions component, and
         char key = extension.visit(
             [](::Locale::LocaleExtension const&) { return 'u'; },
             [](::Locale::TransformedExtension const&) { return 't'; },
             [](::Locale::OtherExtension const& ext) { return static_cast<char>(to_ascii_lowercase(ext.key)); });
 
-        if (unique_keys.contains_slow(key))
-            return {};
+        // a. If extensions contains any duplicate singleton subtags, return false.
+        if (unique_keys.set(key) != HashSetResult::InsertedNewEntry)
+            return false;
 
-        unique_keys.append(key);
-
-        // if a transformed_extensions component that contains a tlang component is present, then
-        // the tlang component contains no duplicate unicode_variant_subtag subtags.
+        // b. Let transformExtension be the longest substring of extensions matched by the transformed_extensions Unicode
+        //    locale nonterminal. If there is no such substring, return true.
         if (auto* transformed = extension.get_pointer<::Locale::TransformedExtension>()) {
-            auto& language = transformed->language;
-            if (language.has_value() && contains_duplicate_variant(language->variants))
-                return {};
+            // c. Assert: The substring of transformExtension from 0 to 3 is "-t-".
+            // d. Let tPrefix be the substring of transformExtension from 3.
+
+            // e. Let tlang be the longest prefix of tPrefix matched by the tlang Unicode locale nonterminal. If there is
+            //    no such prefix, return true.
+            auto& transformed_language = transformed->language;
+            if (!transformed_language.has_value())
+                continue;
+
+            // f. Let tlangRefinements be the longest suffix of tlang following a non-empty prefix matched by the
+            //    unicode_language_subtag Unicode locale nonterminal.
+            auto& transformed_refinements = transformed_language->variants;
+
+            // g. If tlangRefinements contains any duplicate substrings matched greedily by the unicode_variant_subtag
+            //    Unicode locale nonterminal, return false.
+            if (contains_duplicate_variant(transformed_refinements))
+                return false;
         }
     }
 
-    return locale_id;
+    // 10. Return true.
+    return true;
 }
 
 // 6.2.3 CanonicalizeUnicodeLocaleId ( locale ), https://tc39.es/ecma402/#sec-canonicalizeunicodelocaleid
-String canonicalize_unicode_locale_id(::Locale::LocaleID& locale)
+String canonicalize_unicode_locale_id(StringView locale)
 {
-    // Note: This implementation differs from the spec in how Step 3 is implemented. The spec assumes
-    // the input to this method is a string, and is written such that operations are performed on parts
-    // of that string. LibUnicode gives us the parsed locale in a structure, so we can mutate that
-    // structure directly. From a footnote in the spec:
-    //
-    // The third step of this algorithm ensures that a Unicode locale extension sequence in the
-    // returned language tag contains:
-    //     * only the first instance of any attribute duplicated in the input, and
-    //     * only the first keyword for a given key in the input.
-    for (auto& extension : locale.extensions) {
-        if (!extension.has<::Locale::LocaleExtension>())
-            continue;
-
-        auto& locale_extension = extension.get<::Locale::LocaleExtension>();
-
-        auto attributes = move(locale_extension.attributes);
-        for (auto& attribute : attributes) {
-            if (!locale_extension.attributes.contains_slow(attribute))
-                locale_extension.attributes.append(move(attribute));
-        }
-
-        auto keywords = move(locale_extension.keywords);
-        for (auto& keyword : keywords) {
-            if (!any_of(locale_extension.keywords, [&](auto const& k) { return k.key == keyword.key; }))
-                locale_extension.keywords.append(move(keyword));
-        }
-
-        break;
-    }
-
-    // 1. Let localeId be the string locale after performing the algorithm to transform it to canonical syntax per Unicode Technical Standard #35 LDML § 3.2.1 Canonical Unicode Locale Identifiers.
-    // 2. Let localeId be the string localeId after performing the algorithm to transform it to canonical form.
-    auto locale_id = ::Locale::canonicalize_unicode_locale_id(locale);
-    VERIFY(locale_id.has_value());
-
-    // 4. Return localeId.
-    return locale_id.release_value();
+    return ::Locale::canonicalize_unicode_locale_id(locale);
 }
 
 // 6.3.1 IsWellFormedCurrencyCode ( currency ), https://tc39.es/ecma402/#sec-iswellformedcurrencycode
@@ -246,12 +234,11 @@ ThrowCompletionOr<Vector<String>> canonicalize_locale_list(VM& vm, Value locales
             }
 
             // v. If ! IsStructurallyValidLanguageTag(tag) is false, throw a RangeError exception.
-            auto locale_id = is_structurally_valid_language_tag(tag);
-            if (!locale_id.has_value())
+            if (!is_structurally_valid_language_tag(tag))
                 return vm.throw_completion<RangeError>(ErrorType::IntlInvalidLanguageTag, tag);
 
             // vi. Let canonicalizedTag be ! CanonicalizeUnicodeLocaleId(tag).
-            auto canonicalized_tag = JS::Intl::canonicalize_unicode_locale_id(*locale_id);
+            auto canonicalized_tag = canonicalize_unicode_locale_id(tag);
 
             // vii. If canonicalizedTag is not an element of seen, append canonicalizedTag as the last element of seen.
             if (!seen.contains_slow(canonicalized_tag))
@@ -355,7 +342,7 @@ String insert_unicode_extension_and_canonicalize(::Locale::LocaleID locale, ::Lo
     // structure directly.
     locale.extensions.append(move(extension));
 
-    return JS::Intl::canonicalize_unicode_locale_id(locale);
+    return JS::Intl::canonicalize_unicode_locale_id(locale.to_string());
 }
 
 template<typename T>
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/AbstractOperations.h b/Userland/Libraries/LibJS/Runtime/Intl/AbstractOperations.h
index a4a3e1a0208..ea1593adf68 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/AbstractOperations.h
+++ b/Userland/Libraries/LibJS/Runtime/Intl/AbstractOperations.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2021-2024, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -81,8 +81,8 @@ struct PatternPartitionWithSource : public PatternPartition {
 
 using StringOrBoolean = Variant<StringView, bool>;
 
-Optional<::Locale::LocaleID> is_structurally_valid_language_tag(StringView locale);
-String canonicalize_unicode_locale_id(::Locale::LocaleID& locale);
+bool is_structurally_valid_language_tag(StringView locale);
+String canonicalize_unicode_locale_id(StringView locale);
 bool is_well_formed_currency_code(StringView currency);
 bool is_well_formed_unit_identifier(StringView unit_identifier);
 ThrowCompletionOr<Vector<String>> canonicalize_locale_list(VM&, Value locales);
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/DisplayNames.cpp b/Userland/Libraries/LibJS/Runtime/Intl/DisplayNames.cpp
index 37ed147a7b6..a3e5c3923bc 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/DisplayNames.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/DisplayNames.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2022, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2021-2024, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -78,30 +78,6 @@ StringView DisplayNames::fallback_string() const
     }
 }
 
-void DisplayNames::set_language_display(StringView language_display)
-{
-    if (language_display == "dialect"sv)
-        m_language_display = LanguageDisplay::Dialect;
-    else if (language_display == "standard"sv)
-        m_language_display = LanguageDisplay::Standard;
-    else
-        VERIFY_NOT_REACHED();
-}
-
-StringView DisplayNames::language_display_string() const
-{
-    VERIFY(m_language_display.has_value());
-
-    switch (*m_language_display) {
-    case LanguageDisplay::Dialect:
-        return "dialect"sv;
-    case LanguageDisplay::Standard:
-        return "standard"sv;
-    default:
-        VERIFY_NOT_REACHED();
-    }
-}
-
 // 12.5.1 CanonicalCodeForDisplayNames ( type, code ), https://tc39.es/ecma402/#sec-canonicalcodefordisplaynames
 ThrowCompletionOr<Value> canonical_code_for_display_names(VM& vm, DisplayNames::Type type, StringView code)
 {
@@ -112,12 +88,11 @@ ThrowCompletionOr<Value> canonical_code_for_display_names(VM& vm, DisplayNames::
             return vm.throw_completion<RangeError>(ErrorType::OptionIsNotValidValue, code, "language"sv);
 
         // b. If IsStructurallyValidLanguageTag(code) is false, throw a RangeError exception.
-        auto locale_id = is_structurally_valid_language_tag(code);
-        if (!locale_id.has_value())
+        if (!is_structurally_valid_language_tag(code))
             return vm.throw_completion<RangeError>(ErrorType::IntlInvalidLanguageTag, code);
 
         // c. Return ! CanonicalizeUnicodeLocaleId(code).
-        auto canonicalized_tag = JS::Intl::canonicalize_unicode_locale_id(*locale_id);
+        auto canonicalized_tag = canonicalize_unicode_locale_id(code);
         return PrimitiveString::create(vm, move(canonicalized_tag));
     }
 
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/DisplayNames.h b/Userland/Libraries/LibJS/Runtime/Intl/DisplayNames.h
index b10056ccfcd..905ab331678 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/DisplayNames.h
+++ b/Userland/Libraries/LibJS/Runtime/Intl/DisplayNames.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2022, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2021-2024, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -10,6 +10,7 @@
 #include <AK/String.h>
 #include <AK/StringView.h>
 #include <LibJS/Runtime/Object.h>
+#include <LibLocale/DisplayNames.h>
 #include <LibLocale/Locale.h>
 
 namespace JS::Intl {
@@ -34,11 +35,6 @@ class DisplayNames final : public Object {
         Code,
     };
 
-    enum class LanguageDisplay {
-        Dialect,
-        Standard,
-    };
-
 public:
     virtual ~DisplayNames() override = default;
 
@@ -58,18 +54,18 @@ public:
     StringView fallback_string() const;
 
     bool has_language_display() const { return m_language_display.has_value(); }
-    LanguageDisplay language_display() const { return *m_language_display; }
-    void set_language_display(StringView language_display);
-    StringView language_display_string() const;
+    ::Locale::LanguageDisplay language_display() const { return *m_language_display; }
+    void set_language_display(StringView language_display) { m_language_display = ::Locale::language_display_from_string(language_display); }
+    StringView language_display_string() const { return ::Locale::language_display_to_string(*m_language_display); }
 
 private:
     DisplayNames(Object& prototype);
 
-    String m_locale;                                   // [[Locale]]
-    ::Locale::Style m_style { ::Locale::Style::Long }; // [[Style]]
-    Type m_type { Type::Invalid };                     // [[Type]]
-    Fallback m_fallback { Fallback::Invalid };         // [[Fallback]]
-    Optional<LanguageDisplay> m_language_display {};   // [[LanguageDisplay]]
+    String m_locale;                                        // [[Locale]]
+    ::Locale::Style m_style { ::Locale::Style::Long };      // [[Style]]
+    Type m_type { Type::Invalid };                          // [[Type]]
+    Fallback m_fallback { Fallback::Invalid };              // [[Fallback]]
+    Optional<::Locale::LanguageDisplay> m_language_display; // [[LanguageDisplay]]
 };
 
 ThrowCompletionOr<Value> canonical_code_for_display_names(VM&, DisplayNames::Type, StringView code);
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/DisplayNamesPrototype.cpp b/Userland/Libraries/LibJS/Runtime/Intl/DisplayNamesPrototype.cpp
index c30f3982f1a..89c7aac6263 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/DisplayNamesPrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/DisplayNamesPrototype.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2022, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2021-2024, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -9,7 +9,7 @@
 #include <LibJS/Runtime/Intl/AbstractOperations.h>
 #include <LibJS/Runtime/Intl/DisplayNames.h>
 #include <LibJS/Runtime/Intl/DisplayNamesPrototype.h>
-#include <LibLocale/Locale.h>
+#include <LibLocale/DisplayNames.h>
 
 namespace JS::Intl {
 
@@ -53,58 +53,26 @@ JS_DEFINE_NATIVE_FUNCTION(DisplayNamesPrototype::of)
 
     // 5. Let fields be displayNames.[[Fields]].
     // 6. If fields has a field [[<code>]], return fields.[[<code>]].
-    Optional<StringView> result;
-    Optional<String> formatted_result;
+    Optional<String> result;
 
     switch (display_names->type()) {
     case DisplayNames::Type::Language:
-        if (display_names->language_display() == DisplayNames::LanguageDisplay::Dialect) {
-            result = ::Locale::get_locale_language_mapping(display_names->locale(), code_string);
-            if (result.has_value())
-                break;
-        }
-
-        if (auto locale = is_structurally_valid_language_tag(code_string); locale.has_value())
-            formatted_result = ::Locale::format_locale_for_display(display_names->locale(), locale.release_value());
+        result = ::Locale::language_display_name(display_names->locale(), code_string, display_names->language_display());
         break;
     case DisplayNames::Type::Region:
-        result = ::Locale::get_locale_territory_mapping(display_names->locale(), code_string);
+        result = ::Locale::region_display_name(display_names->locale(), code_string);
         break;
     case DisplayNames::Type::Script:
-        result = ::Locale::get_locale_script_mapping(display_names->locale(), code_string);
+        result = ::Locale::script_display_name(display_names->locale(), code_string);
         break;
     case DisplayNames::Type::Currency:
-        switch (display_names->style()) {
-        case ::Locale::Style::Long:
-            result = ::Locale::get_locale_long_currency_mapping(display_names->locale(), code_string);
-            break;
-        case ::Locale::Style::Short:
-            result = ::Locale::get_locale_short_currency_mapping(display_names->locale(), code_string);
-            break;
-        case ::Locale::Style::Narrow:
-            result = ::Locale::get_locale_narrow_currency_mapping(display_names->locale(), code_string);
-            break;
-        default:
-            VERIFY_NOT_REACHED();
-        }
+        result = ::Locale::currency_display_name(display_names->locale(), code_string, display_names->style());
         break;
     case DisplayNames::Type::Calendar:
-        result = ::Locale::get_locale_calendar_mapping(display_names->locale(), code_string);
+        result = ::Locale::calendar_display_name(display_names->locale(), code_string);
         break;
     case DisplayNames::Type::DateTimeField:
-        switch (display_names->style()) {
-        case ::Locale::Style::Long:
-            result = ::Locale::get_locale_long_date_field_mapping(display_names->locale(), code_string);
-            break;
-        case ::Locale::Style::Short:
-            result = ::Locale::get_locale_short_date_field_mapping(display_names->locale(), code_string);
-            break;
-        case ::Locale::Style::Narrow:
-            result = ::Locale::get_locale_narrow_date_field_mapping(display_names->locale(), code_string);
-            break;
-        default:
-            VERIFY_NOT_REACHED();
-        }
+        result = ::Locale::date_time_field_display_name(display_names->locale(), code_string, display_names->style());
         break;
     default:
         VERIFY_NOT_REACHED();
@@ -112,8 +80,6 @@ JS_DEFINE_NATIVE_FUNCTION(DisplayNamesPrototype::of)
 
     if (result.has_value())
         return PrimitiveString::create(vm, result.release_value());
-    if (formatted_result.has_value())
-        return PrimitiveString::create(vm, formatted_result.release_value());
 
     // 7. If displayNames.[[Fallback]] is "code", return code.
     if (display_names->fallback() == DisplayNames::Fallback::Code)
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/Intl.cpp b/Userland/Libraries/LibJS/Runtime/Intl/Intl.cpp
index 3b12bf94e3a..3102ce80f22 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/Intl.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/Intl.cpp
@@ -116,7 +116,7 @@ JS_DEFINE_NATIVE_FUNCTION(Intl::supported_values_of)
     // 1. Let key be ? ToString(key).
     auto key = TRY(vm.argument(0).to_string(vm));
 
-    ReadonlySpan<StringView> list;
+    Optional<Variant<ReadonlySpan<StringView>, ReadonlySpan<String>>> list;
 
     // 2. If key is "calendar", then
     if (key == "calendar"sv) {
@@ -131,7 +131,8 @@ JS_DEFINE_NATIVE_FUNCTION(Intl::supported_values_of)
     // 4. Else if key is "currency", then
     else if (key == "currency"sv) {
         // a. Let list be ! AvailableCanonicalCurrencies( ).
-        list = ::Locale::get_available_currencies();
+        static auto const currencies = ::Locale::available_currencies();
+        list = currencies.span();
     }
     // 5. Else if key is "numberingSystem", then
     else if (key == "numberingSystem"sv) {
@@ -141,13 +142,13 @@ JS_DEFINE_NATIVE_FUNCTION(Intl::supported_values_of)
     // 6. Else if key is "timeZone", then
     else if (key == "timeZone"sv) {
         // a. Let list be ! AvailableCanonicalTimeZones( ).
-        static auto time_zones = available_canonical_time_zones();
+        static auto const time_zones = available_canonical_time_zones();
         list = time_zones.span();
     }
     // 7. Else if key is "unit", then
     else if (key == "unit"sv) {
         // a. Let list be ! AvailableCanonicalUnits( ).
-        static auto units = sanctioned_single_unit_identifiers();
+        static auto const units = sanctioned_single_unit_identifiers();
         list = units.span();
     }
     // 8. Else,
@@ -157,8 +158,10 @@ JS_DEFINE_NATIVE_FUNCTION(Intl::supported_values_of)
     }
 
     // 9. Return CreateArrayFromList( list ).
-    return Array::create_from<StringView>(realm, list, [&](auto value) {
-        return PrimitiveString::create(vm, value);
+    return list->visit([&]<typename T>(ReadonlySpan<T> list) {
+        return Array::create_from<T>(realm, list, [&](auto value) {
+            return PrimitiveString::create(vm, value);
+        });
     });
 }
 
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/LocaleConstructor.cpp b/Userland/Libraries/LibJS/Runtime/Intl/LocaleConstructor.cpp
index 3f8a042d4f2..186b3270996 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/LocaleConstructor.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/LocaleConstructor.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2023, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2021-2024, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -49,8 +49,7 @@ static ThrowCompletionOr<String> apply_options_to_tag(VM& vm, StringView tag, Ob
     // 2. Assert: Type(options) is Object.
 
     // 3. If ! IsStructurallyValidLanguageTag(tag) is false, throw a RangeError exception.
-    auto locale_id = is_structurally_valid_language_tag(tag);
-    if (!locale_id.has_value())
+    if (!is_structurally_valid_language_tag(tag))
         return vm.throw_completion<RangeError>(ErrorType::IntlInvalidLanguageTag, tag);
 
     // 4. Let language be ? GetOption(options, "language", string, empty, undefined).
@@ -69,10 +68,10 @@ static ThrowCompletionOr<String> apply_options_to_tag(VM& vm, StringView tag, Ob
     auto region = TRY(get_string_option(vm, options, vm.names.region, ::Locale::is_unicode_region_subtag));
 
     // 10. Set tag to ! CanonicalizeUnicodeLocaleId(tag).
-    auto canonicalized_tag = JS::Intl::canonicalize_unicode_locale_id(*locale_id);
+    auto canonicalized_tag = JS::Intl::canonicalize_unicode_locale_id(tag);
 
     // 11. Assert: tag matches the unicode_locale_id production.
-    locale_id = ::Locale::parse_unicode_locale_id(canonicalized_tag);
+    auto locale_id = ::Locale::parse_unicode_locale_id(canonicalized_tag);
     VERIFY(locale_id.has_value());
 
     // 12. Let languageId be the substring of tag corresponding to the unicode_language_id production.
@@ -103,8 +102,10 @@ static ThrowCompletionOr<String> apply_options_to_tag(VM& vm, StringView tag, Ob
     }
 
     // 16. Set tag to tag with the substring corresponding to the unicode_language_id production replaced by the string languageId.
+    canonicalized_tag = locale_id->to_string();
+
     // 17. Return ! CanonicalizeUnicodeLocaleId(tag).
-    return JS::Intl::canonicalize_unicode_locale_id(*locale_id);
+    return JS::Intl::canonicalize_unicode_locale_id(canonicalized_tag);
 }
 
 // 14.1.3 ApplyUnicodeExtensionToTag ( tag, options, relevantExtensionKeys ), https://tc39.es/ecma402/#sec-apply-unicode-extension-to-tag
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.cpp b/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.cpp
index b11a53098c1..e03c9a984fb 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2023, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2021-2024, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -16,6 +16,7 @@
 #include <LibJS/Runtime/Intl/NumberFormatFunction.h>
 #include <LibJS/Runtime/Intl/PluralRules.h>
 #include <LibJS/Runtime/ValueInlines.h>
+#include <LibLocale/DisplayNames.h>
 #include <LibUnicode/CurrencyCode.h>
 #include <math.h>
 #include <stdlib.h>
@@ -99,13 +100,13 @@ StringView NumberFormat::resolve_currency_display()
         m_resolved_currency_display = currency();
         break;
     case NumberFormat::CurrencyDisplay::Symbol:
-        m_resolved_currency_display = ::Locale::get_locale_short_currency_mapping(data_locale(), currency());
+        m_resolved_currency_display = ::Locale::currency_display_name(data_locale(), currency(), ::Locale::Style::Short);
         break;
     case NumberFormat::CurrencyDisplay::NarrowSymbol:
-        m_resolved_currency_display = ::Locale::get_locale_narrow_currency_mapping(data_locale(), currency());
+        m_resolved_currency_display = ::Locale::currency_display_name(data_locale(), currency(), ::Locale::Style::Narrow);
         break;
     case NumberFormat::CurrencyDisplay::Name:
-        m_resolved_currency_display = ::Locale::get_locale_numeric_currency_mapping(data_locale(), currency());
+        m_resolved_currency_display = ::Locale::currency_numeric_display_name(data_locale(), currency());
         break;
     default:
         VERIFY_NOT_REACHED();
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.h b/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.h
index 700dcbdd78a..55dc2bc6934 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.h
+++ b/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2023, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2021-2024, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -268,7 +268,7 @@ private:
     GCPtr<NativeFunction> m_bound_format;                // [[BoundFormat]]
 
     // Non-standard. Stores the resolved currency display string based on [[Locale]], [[Currency]], and [[CurrencyDisplay]].
-    Optional<StringView> m_resolved_currency_display;
+    Optional<String> m_resolved_currency_display;
 
     // Non-standard. Stores the resolved compact number format based on [[Locale]], [[Notation], [[Style]], and [[CompactDisplay]].
     Optional<::Locale::NumberFormat> m_compact_format;
diff --git a/Userland/Libraries/LibJS/Tests/builtins/Intl/Intl.getCanonicalLocales.js b/Userland/Libraries/LibJS/Tests/builtins/Intl/Intl.getCanonicalLocales.js
index bda470aa460..1fde5a9b730 100644
--- a/Userland/Libraries/LibJS/Tests/builtins/Intl/Intl.getCanonicalLocales.js
+++ b/Userland/Libraries/LibJS/Tests/builtins/Intl/Intl.getCanonicalLocales.js
@@ -88,8 +88,8 @@ describe("normal behavior", () => {
         expect(Intl.getCanonicalLocales(["EN-US"])).toEqual(["en-US"]);
         expect(Intl.getCanonicalLocales(["EN-US", "Fr"])).toEqual(["en-US", "fr"]);
         expect(Intl.getCanonicalLocales("EN-lATN-US")).toEqual(["en-Latn-US"]);
-        expect(Intl.getCanonicalLocales("EN-US-POSIX")).toEqual(["en-US-posix"]);
-        expect(Intl.getCanonicalLocales("EN-LATN-US-POSIX")).toEqual(["en-Latn-US-posix"]);
+        expect(Intl.getCanonicalLocales("EN-US-POSIX")).toEqual(["en-US-u-va-posix"]);
+        expect(Intl.getCanonicalLocales("EN-LATN-US-POSIX")).toEqual(["en-Latn-US-u-va-posix"]);
     });
 
     test("duplicate locales", () => {
diff --git a/Userland/Libraries/LibLocale/CMakeLists.txt b/Userland/Libraries/LibLocale/CMakeLists.txt
index 3f9df1ffcb0..a944cefdc97 100644
--- a/Userland/Libraries/LibLocale/CMakeLists.txt
+++ b/Userland/Libraries/LibLocale/CMakeLists.txt
@@ -11,6 +11,8 @@ endif()
 
 set(SOURCES
     DateTimeFormat.cpp
+    DisplayNames.cpp
+    ICU.cpp
     Locale.cpp
     NumberFormat.cpp
     PluralRules.cpp
diff --git a/Userland/Libraries/LibLocale/DisplayNames.cpp b/Userland/Libraries/LibLocale/DisplayNames.cpp
new file mode 100644
index 00000000000..a1fa1585f1f
--- /dev/null
+++ b/Userland/Libraries/LibLocale/DisplayNames.cpp
@@ -0,0 +1,242 @@
+/*
+ * Copyright (c) 2024, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#define AK_DONT_REPLACE_STD
+
+#include <AK/Array.h>
+#include <LibLocale/DisplayNames.h>
+#include <LibLocale/ICU.h>
+
+#include <unicode/dtptngen.h>
+#include <unicode/localebuilder.h>
+#include <unicode/locdspnm.h>
+#include <unicode/udatpg.h>
+
+namespace Locale {
+
+LanguageDisplay language_display_from_string(StringView language_display)
+{
+    if (language_display == "standard"sv)
+        return LanguageDisplay::Standard;
+    if (language_display == "dialect"sv)
+        return LanguageDisplay::Dialect;
+    VERIFY_NOT_REACHED();
+}
+
+StringView language_display_to_string(LanguageDisplay language_display)
+{
+    switch (language_display) {
+    case LanguageDisplay::Standard:
+        return "standard"sv;
+    case LanguageDisplay::Dialect:
+        return "dialect"sv;
+    default:
+        VERIFY_NOT_REACHED();
+    }
+}
+
+Optional<String> language_display_name(StringView locale, StringView language, LanguageDisplay display)
+{
+    auto locale_data = LocaleData::for_locale(locale);
+    if (!locale_data.has_value())
+        return {};
+
+    auto language_data = LocaleData::for_locale(language);
+    if (!language_data.has_value())
+        return {};
+
+    auto& display_names = display == LanguageDisplay::Standard
+        ? locale_data->standard_display_names()
+        : locale_data->dialect_display_names();
+
+    icu::UnicodeString result;
+    display_names.localeDisplayName(language_data->locale().getName(), result);
+
+    return icu_string_to_string(result);
+}
+
+Optional<String> region_display_name(StringView locale, StringView region)
+{
+    UErrorCode status = U_ZERO_ERROR;
+
+    auto locale_data = LocaleData::for_locale(locale);
+    if (!locale_data.has_value())
+        return {};
+
+    auto icu_region = icu::LocaleBuilder().setRegion(icu_string_piece(region)).build(status);
+    if (icu_failure(status))
+        return {};
+
+    icu::UnicodeString result;
+    locale_data->standard_display_names().regionDisplayName(icu_region.getCountry(), result);
+
+    return icu_string_to_string(result);
+}
+
+Optional<String> script_display_name(StringView locale, StringView script)
+{
+    UErrorCode status = U_ZERO_ERROR;
+
+    auto locale_data = LocaleData::for_locale(locale);
+    if (!locale_data.has_value())
+        return {};
+
+    auto icu_script = icu::LocaleBuilder().setScript(icu_string_piece(script)).build(status);
+    if (icu_failure(status))
+        return {};
+
+    icu::UnicodeString result;
+    locale_data->standard_display_names().scriptDisplayName(icu_script.getScript(), result);
+
+    return icu_string_to_string(result);
+}
+
+Optional<String> calendar_display_name(StringView locale, StringView calendar)
+{
+    auto locale_data = LocaleData::for_locale(locale);
+    if (!locale_data.has_value())
+        return {};
+
+    if (calendar == "gregory"sv)
+        calendar = "gregorian"sv;
+    if (calendar == "islamicc"sv)
+        calendar = "islamic-civil"sv;
+    if (calendar == "ethioaa"sv)
+        calendar = "ethiopic-amete-alem"sv;
+
+    icu::UnicodeString result;
+    locale_data->standard_display_names().keyValueDisplayName("calendar", ByteString(calendar).characters(), result);
+
+    return icu_string_to_string(result);
+}
+
+static constexpr UDateTimePatternField icu_date_time_field(StringView field)
+{
+    if (field == "day"sv)
+        return UDATPG_DAY_FIELD;
+    if (field == "dayPeriod"sv)
+        return UDATPG_DAYPERIOD_FIELD;
+    if (field == "era"sv)
+        return UDATPG_ERA_FIELD;
+    if (field == "hour"sv)
+        return UDATPG_HOUR_FIELD;
+    if (field == "minute"sv)
+        return UDATPG_MINUTE_FIELD;
+    if (field == "month"sv)
+        return UDATPG_MONTH_FIELD;
+    if (field == "quarter"sv)
+        return UDATPG_QUARTER_FIELD;
+    if (field == "second"sv)
+        return UDATPG_SECOND_FIELD;
+    if (field == "timeZoneName"sv)
+        return UDATPG_ZONE_FIELD;
+    if (field == "weekOfYear"sv)
+        return UDATPG_WEEK_OF_YEAR_FIELD;
+    if (field == "weekday"sv)
+        return UDATPG_WEEKDAY_FIELD;
+    if (field == "year"sv)
+        return UDATPG_YEAR_FIELD;
+    VERIFY_NOT_REACHED();
+}
+
+static constexpr UDateTimePGDisplayWidth icu_date_time_style(Style style)
+{
+    switch (style) {
+    case Style::Long:
+        return UDATPG_WIDE;
+    case Style::Short:
+        return UDATPG_ABBREVIATED;
+    case Style::Narrow:
+        return UDATPG_NARROW;
+    }
+
+    VERIFY_NOT_REACHED();
+}
+
+Optional<String> date_time_field_display_name(StringView locale, StringView field, Style style)
+{
+    auto locale_data = LocaleData::for_locale(locale);
+    if (!locale_data.has_value())
+        return {};
+
+    auto icu_field = icu_date_time_field(field);
+    auto icu_style = icu_date_time_style(style);
+
+    icu::UnicodeString result;
+    result = locale_data->date_time_pattern_generator().getFieldDisplayName(icu_field, icu_style);
+
+    return icu_string_to_string(result);
+}
+
+static constexpr Array<UChar, 4> icu_currency_code(StringView currency)
+{
+    VERIFY(currency.length() == 3);
+
+    return to_array({
+        static_cast<UChar>(currency[0]),
+        static_cast<UChar>(currency[1]),
+        static_cast<UChar>(currency[2]),
+        u'\0',
+    });
+}
+
+static constexpr UCurrNameStyle icu_currency_style(Style style)
+{
+    switch (style) {
+    case Style::Long:
+        return UCURR_LONG_NAME;
+    case Style::Short:
+        return UCURR_SYMBOL_NAME;
+    case Style::Narrow:
+        return UCURR_NARROW_SYMBOL_NAME;
+    }
+
+    VERIFY_NOT_REACHED();
+}
+
+Optional<String> currency_display_name(StringView locale, StringView currency, Style style)
+{
+    UErrorCode status = U_ZERO_ERROR;
+
+    auto locale_data = LocaleData::for_locale(locale);
+    if (!locale_data.has_value())
+        return {};
+
+    auto icu_currency = icu_currency_code(currency);
+
+    i32 length = 0;
+    UChar const* result = ucurr_getName(icu_currency.data(), locale_data->locale().getName(), icu_currency_style(style), nullptr, &length, &status);
+
+    if (icu_failure(status))
+        return {};
+    if ((status == U_USING_DEFAULT_WARNING) && (result == icu_currency.data()))
+        return {};
+
+    return icu_string_to_string(result, length);
+}
+
+Optional<String> currency_numeric_display_name(StringView locale, StringView currency)
+{
+    UErrorCode status = U_ZERO_ERROR;
+
+    auto locale_data = LocaleData::for_locale(locale);
+    if (!locale_data.has_value())
+        return {};
+
+    auto icu_currency = icu_currency_code(currency);
+
+    i32 length = 0;
+    UChar const* result = ucurr_getPluralName(icu_currency.data(), locale_data->locale().getName(), nullptr, "other", &length, &status);
+
+    if (icu_failure(status))
+        return {};
+    if ((status == U_USING_DEFAULT_WARNING) && (result == icu_currency.data()))
+        return {};
+
+    return icu_string_to_string(result, length);
+}
+
+}
diff --git a/Userland/Libraries/LibLocale/DisplayNames.h b/Userland/Libraries/LibLocale/DisplayNames.h
new file mode 100644
index 00000000000..30b34438622
--- /dev/null
+++ b/Userland/Libraries/LibLocale/DisplayNames.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2024, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Optional.h>
+#include <AK/String.h>
+#include <AK/StringView.h>
+#include <LibLocale/Locale.h>
+
+namespace Locale {
+
+enum class LanguageDisplay {
+    Standard,
+    Dialect,
+};
+
+LanguageDisplay language_display_from_string(StringView language_display);
+StringView language_display_to_string(LanguageDisplay language_display);
+
+Optional<String> language_display_name(StringView locale, StringView language, LanguageDisplay);
+Optional<String> region_display_name(StringView locale, StringView region);
+Optional<String> script_display_name(StringView locale, StringView script);
+Optional<String> calendar_display_name(StringView locale, StringView calendar);
+Optional<String> date_time_field_display_name(StringView locale, StringView field, Style);
+Optional<String> currency_display_name(StringView locale, StringView currency, Style);
+Optional<String> currency_numeric_display_name(StringView locale, StringView currency);
+
+}
diff --git a/Userland/Libraries/LibLocale/Forward.h b/Userland/Libraries/LibLocale/Forward.h
index b503f19feb4..dc1fa2b0854 100644
--- a/Userland/Libraries/LibLocale/Forward.h
+++ b/Userland/Libraries/LibLocale/Forward.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2022, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2021-2024, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -15,9 +15,6 @@ enum class CalendarPatternStyle : u8;
 enum class CalendarSymbol : u8;
 enum class CharacterOrder : u8;
 enum class CompactNumberFormatType : u8;
-enum class Condition : u8;
-enum class Currency : u16;
-enum class DateField : u8;
 enum class DayPeriod : u8;
 enum class Era : u8;
 enum class FirstDayRegion : u8;
@@ -30,17 +27,14 @@ enum class KeywordColCaseFirst : u8;
 enum class KeywordColNumeric : u8;
 enum class KeywordHours : u8;
 enum class KeywordNumbers : u8;
-enum class Language : u16;
 enum class ListPatternType : u8;
 enum class Locale : u16;
 enum class MinimumDaysRegion : u8;
 enum class Month : u8;
 enum class NumericSymbol : u8;
 enum class PluralCategory : u8;
-enum class ScriptTag : u8;
 enum class StandardNumberFormatType : u8;
 enum class Style : u8;
-enum class Territory : u8;
 enum class Weekday : u8;
 enum class WeekendEndRegion : u8;
 enum class WeekendStartRegion : u8;
diff --git a/Userland/Libraries/LibLocale/ICU.cpp b/Userland/Libraries/LibLocale/ICU.cpp
new file mode 100644
index 00000000000..35e2dc475fa
--- /dev/null
+++ b/Userland/Libraries/LibLocale/ICU.cpp
@@ -0,0 +1,104 @@
+/*
+ * Copyright (c) 2024, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#define AK_DONT_REPLACE_STD
+
+#include <AK/HashMap.h>
+#include <AK/NonnullOwnPtr.h>
+#include <AK/Utf16View.h>
+#include <LibLocale/ICU.h>
+
+#include <unicode/dtptngen.h>
+#include <unicode/locdspnm.h>
+#include <unicode/unistr.h>
+
+namespace Locale {
+
+static HashMap<String, OwnPtr<LocaleData>> s_locale_cache;
+
+Optional<LocaleData&> LocaleData::for_locale(StringView locale)
+{
+    auto locale_data = s_locale_cache.get(locale);
+
+    if (!locale_data.has_value()) {
+        locale_data = s_locale_cache.ensure(MUST(String::from_utf8(locale)), [&]() -> OwnPtr<LocaleData> {
+            UErrorCode status = U_ZERO_ERROR;
+
+            auto icu_locale = icu::Locale::forLanguageTag(icu_string_piece(locale), status);
+            if (icu_failure(status))
+                return nullptr;
+
+            return adopt_own(*new LocaleData { move(icu_locale) });
+        });
+    }
+
+    if (locale_data.value())
+        return *locale_data.value();
+    return {};
+}
+
+LocaleData::LocaleData(icu::Locale locale)
+    : m_locale(move(locale))
+{
+}
+
+String LocaleData::to_string()
+{
+    if (!m_locale_string.has_value()) {
+        UErrorCode status = U_ZERO_ERROR;
+
+        auto result = locale().toLanguageTag<StringBuilder>(status);
+        VERIFY(icu_success(status));
+
+        m_locale_string = MUST(result.to_string());
+    }
+
+    return *m_locale_string;
+}
+
+icu::LocaleDisplayNames& LocaleData::standard_display_names()
+{
+    if (!m_standard_display_names)
+        m_standard_display_names = adopt_own(*icu::LocaleDisplayNames::createInstance(locale()));
+    return *m_standard_display_names;
+}
+
+icu::LocaleDisplayNames& LocaleData::dialect_display_names()
+{
+    if (!m_dialect_display_names)
+        m_dialect_display_names = adopt_own(*icu::LocaleDisplayNames::createInstance(locale(), ULDN_DIALECT_NAMES));
+    return *m_dialect_display_names;
+}
+
+icu::DateTimePatternGenerator& LocaleData::date_time_pattern_generator()
+{
+    if (!m_date_time_pattern_generator) {
+        UErrorCode status = U_ZERO_ERROR;
+
+        m_date_time_pattern_generator = adopt_own(*icu::DateTimePatternGenerator::createInstance(locale(), status));
+        VERIFY(icu_success(status));
+    }
+
+    return *m_date_time_pattern_generator;
+}
+
+icu::StringPiece icu_string_piece(StringView string)
+{
+    return { string.characters_without_null_termination(), static_cast<i32>(string.length()) };
+}
+
+String icu_string_to_string(icu::UnicodeString const& string)
+{
+    return icu_string_to_string(string.getBuffer(), string.length());
+}
+
+String icu_string_to_string(UChar const* string, i32 length)
+{
+    ReadonlySpan<u16> view { reinterpret_cast<u16 const*>(string), static_cast<size_t>(length) };
+    return MUST(Utf16View { view }.to_utf8());
+}
+
+}
diff --git a/Userland/Libraries/LibLocale/ICU.h b/Userland/Libraries/LibLocale/ICU.h
new file mode 100644
index 00000000000..99b998354ad
--- /dev/null
+++ b/Userland/Libraries/LibLocale/ICU.h
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2024, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#define AK_DONT_REPLACE_STD
+
+#include <AK/Optional.h>
+#include <AK/OwnPtr.h>
+#include <AK/String.h>
+#include <AK/StringView.h>
+
+#include <unicode/locid.h>
+#include <unicode/stringpiece.h>
+#include <unicode/utypes.h>
+#include <unicode/uversion.h>
+
+U_NAMESPACE_BEGIN
+class DateTimePatternGenerator;
+class LocaleDisplayNames;
+class UnicodeString;
+U_NAMESPACE_END
+
+namespace Locale {
+
+class LocaleData {
+public:
+    static Optional<LocaleData&> for_locale(StringView locale);
+
+    ALWAYS_INLINE icu::Locale& locale() { return m_locale; }
+
+    String to_string();
+
+    icu::LocaleDisplayNames& standard_display_names();
+    icu::LocaleDisplayNames& dialect_display_names();
+
+    icu::DateTimePatternGenerator& date_time_pattern_generator();
+
+private:
+    explicit LocaleData(icu::Locale locale);
+
+    icu::Locale m_locale;
+    Optional<String> m_locale_string;
+
+    OwnPtr<icu::LocaleDisplayNames> m_standard_display_names;
+    OwnPtr<icu::LocaleDisplayNames> m_dialect_display_names;
+    OwnPtr<icu::DateTimePatternGenerator> m_date_time_pattern_generator;
+};
+
+static constexpr bool icu_success(UErrorCode code)
+{
+    return static_cast<bool>(U_SUCCESS(code));
+}
+
+static constexpr bool icu_failure(UErrorCode code)
+{
+    return static_cast<bool>(U_FAILURE(code));
+}
+
+icu::StringPiece icu_string_piece(StringView string);
+String icu_string_to_string(icu::UnicodeString const& string);
+String icu_string_to_string(UChar const*, i32 length);
+
+}
diff --git a/Userland/Libraries/LibLocale/Locale.cpp b/Userland/Libraries/LibLocale/Locale.cpp
index 8ec3bd5548e..2011b7df7c9 100644
--- a/Userland/Libraries/LibLocale/Locale.cpp
+++ b/Userland/Libraries/LibLocale/Locale.cpp
@@ -1,17 +1,25 @@
 /*
- * Copyright (c) 2021-2023, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2021-2024, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#define AK_DONT_REPLACE_STD
+
 #include <AK/AllOf.h>
 #include <AK/GenericLexer.h>
 #include <AK/QuickSort.h>
+#include <AK/ScopeGuard.h>
 #include <AK/StringBuilder.h>
 #include <LibLocale/DateTimeFormat.h>
+#include <LibLocale/ICU.h>
 #include <LibLocale/Locale.h>
 #include <LibUnicode/CharacterTypes.h>
 
+#include <unicode/localebuilder.h>
+#include <unicode/locid.h>
+#include <unicode/ucurr.h>
+
 namespace Locale {
 
 static bool is_key(StringView key)
@@ -473,266 +481,36 @@ Optional<LocaleID> parse_unicode_locale_id(StringView locale)
     return locale_id;
 }
 
-static void perform_hard_coded_key_value_substitutions(StringView key, String& value)
+String canonicalize_unicode_locale_id(StringView locale)
 {
-    // FIXME: In the XML export of CLDR, there are some aliases defined in the following files:
-    // https://github.com/unicode-org/cldr-staging/blob/master/production/common/bcp47/calendar.xml
-    // https://github.com/unicode-org/cldr-staging/blob/master/production/common/bcp47/collation.xml
-    // https://github.com/unicode-org/cldr-staging/blob/master/production/common/bcp47/measure.xml
-    // https://github.com/unicode-org/cldr-staging/blob/master/production/common/bcp47/timezone.xml
-    // https://github.com/unicode-org/cldr-staging/blob/master/production/common/bcp47/transform.xml
-    //
-    // There isn't yet a counterpart in the JSON export. See: https://unicode-org.atlassian.net/browse/CLDR-14571
-    Optional<StringView> result;
+    UErrorCode status = U_ZERO_ERROR;
 
-    if (key == "ca"sv) {
-        if (value == "islamicc"sv)
-            result = "islamic-civil"sv;
-        else if (value == "ethiopic-amete-alem"sv)
-            result = "ethioaa"sv;
-    } else if (key.is_one_of("kb"sv, "kc"sv, "kh"sv, "kk"sv, "kn"sv) && (value == "yes"sv)) {
-        result = "true"sv;
-    } else if (key == "ks"sv) {
-        if (value == "primary"sv)
-            result = "level1"sv;
-        else if (value == "tertiary"sv)
-            result = "level3"sv;
-        // Note: There are also aliases for "secondary", "quaternary", "quarternary", and "identical",
-        // but those are semantically incorrect values (they are too long), so they can be skipped.
-    } else if ((key == "m0"sv) && (value == "names"sv)) {
-        result = "prprname"sv;
-    } else if ((key == "ms"sv) && (value == "imperial"sv)) {
-        result = "uksystem"sv;
-    } else if (key == "tz"sv) {
-        // Formatter disabled because this block is easier to read / check against timezone.xml as one-liners.
-        // clang-format off
-        if (value == "aqams"sv) result = "nzakl"sv;
-        else if (value == "cnckg"sv) result = "cnsha"sv;
-        else if (value == "cnhrb"sv) result = "cnsha"sv;
-        else if (value == "cnkhg"sv) result = "cnurc"sv;
-        else if (value == "cuba"sv) result = "cuhav"sv;
-        else if (value == "egypt"sv) result = "egcai"sv;
-        else if (value == "eire"sv) result = "iedub"sv;
-        else if (value == "est"sv) result = "utcw05"sv;
-        else if (value == "gmt0"sv) result = "gmt"sv;
-        else if (value == "hongkong"sv) result = "hkhkg"sv;
-        else if (value == "hst"sv) result = "utcw10"sv;
-        else if (value == "iceland"sv) result = "isrey"sv;
-        else if (value == "iran"sv) result = "irthr"sv;
-        else if (value == "israel"sv) result = "jeruslm"sv;
-        else if (value == "jamaica"sv) result = "jmkin"sv;
-        else if (value == "japan"sv) result = "jptyo"sv;
-        else if (value == "kwajalein"sv) result = "mhkwa"sv;
-        else if (value == "libya"sv) result = "lytip"sv;
-        else if (value == "mst"sv) result = "utcw07"sv;
-        else if (value == "navajo"sv) result = "usden"sv;
-        else if (value == "poland"sv) result = "plwaw"sv;
-        else if (value == "portugal"sv) result = "ptlis"sv;
-        else if (value == "prc"sv) result = "cnsha"sv;
-        else if (value == "roc"sv) result = "twtpe"sv;
-        else if (value == "rok"sv) result = "krsel"sv;
-        else if (value == "singapore"sv) result = "sgsin"sv;
-        else if (value == "turkey"sv) result = "trist"sv;
-        else if (value == "uct"sv) result = "utc"sv;
-        else if (value == "usnavajo"sv) result = "usden"sv;
-        else if (value == "zulu"sv) result = "utc"sv;
-        // clang-format on
-    }
+    auto locale_data = LocaleData::for_locale(locale);
+    VERIFY(locale_data.has_value());
 
-    if (result.has_value())
-        value = MUST(String::from_utf8(*result));
+    locale_data->locale().canonicalize(status);
+    VERIFY(icu_success(status));
+
+    return locale_data->to_string();
 }
 
-void canonicalize_unicode_extension_values(StringView key, String& value, bool remove_true)
+void canonicalize_unicode_extension_values(StringView key, String& value, bool)
 {
-    value = MUST(value.to_lowercase());
-    perform_hard_coded_key_value_substitutions(key, value);
+    UErrorCode status = U_ZERO_ERROR;
 
-    // Note: The spec says to remove "true" type and tfield values but that is believed to be a bug in the spec
-    // because, for tvalues, that would result in invalid syntax:
-    //     https://unicode-org.atlassian.net/browse/CLDR-14318
-    // This has also been noted by test262:
-    //     https://github.com/tc39/test262/blob/18bb955771669541c56c28748603f6afdb2e25ff/test/intl402/Intl/getCanonicalLocales/transformed-ext-canonical.js
-    if (remove_true && (value == "true"sv)) {
-        value = {};
-        return;
-    }
+    icu::LocaleBuilder builder;
+    builder.setUnicodeLocaleKeyword(icu_string_piece(key), icu_string_piece(value));
 
-    if (key.is_one_of("sd"sv, "rg"sv)) {
-        if (auto alias = resolve_subdivision_alias(value); alias.has_value()) {
-            auto aliases = alias->split_view(' ');
+    auto locale = builder.build(status);
+    VERIFY(icu_success(status));
 
-            // FIXME: Subdivision subtags do not appear in the CLDR likelySubtags.json file.
-            //        Implement the spec's recommendation of using just the first alias for now,
-            //        but we should determine if there's anything else needed here.
-            value = MUST(String::from_utf8(aliases[0]));
-        }
-    }
-}
+    locale.canonicalize(status);
+    VERIFY(icu_success(status));
 
-static void transform_unicode_locale_id_to_canonical_syntax(LocaleID& locale_id)
-{
-    auto canonicalize_language = [&](LanguageID& language_id, bool force_lowercase) {
-        language_id.language = MUST(language_id.language->to_lowercase());
-        if (language_id.script.has_value())
-            language_id.script = MUST(language_id.script->to_titlecase());
-        if (language_id.region.has_value())
-            language_id.region = MUST(language_id.region->to_uppercase());
-        for (auto& variant : language_id.variants)
-            variant = MUST(variant.to_lowercase());
+    auto result = locale.getUnicodeKeywordValue<StringBuilder>(icu_string_piece(key), status);
+    VERIFY(icu_success(status));
 
-        resolve_complex_language_aliases(language_id);
-
-        if (auto alias = resolve_language_alias(*language_id.language); alias.has_value()) {
-            auto language_alias = parse_unicode_language_id(*alias);
-            VERIFY(language_alias.has_value());
-
-            language_id.language = move(language_alias->language);
-            if (!language_id.script.has_value() && language_alias->script.has_value())
-                language_id.script = move(language_alias->script);
-            if (!language_id.region.has_value() && language_alias->region.has_value())
-                language_id.region = move(language_alias->region);
-            if (language_id.variants.is_empty() && !language_alias->variants.is_empty())
-                language_id.variants = move(language_alias->variants);
-        }
-
-        if (language_id.script.has_value()) {
-            if (auto alias = resolve_script_tag_alias(*language_id.script); alias.has_value())
-                language_id.script = MUST(String::from_utf8(*alias));
-        }
-
-        if (language_id.region.has_value()) {
-            if (auto alias = resolve_territory_alias(*language_id.region); alias.has_value())
-                language_id.region = resolve_most_likely_territory_alias(language_id, *alias);
-        }
-
-        quick_sort(language_id.variants);
-
-        for (auto& variant : language_id.variants) {
-            variant = MUST(variant.to_lowercase());
-            if (auto alias = resolve_variant_alias(variant); alias.has_value())
-                variant = MUST(String::from_utf8(*alias));
-        }
-
-        if (force_lowercase) {
-            if (language_id.script.has_value())
-                language_id.script = MUST(language_id.script->to_lowercase());
-            if (language_id.region.has_value())
-                language_id.region = MUST(language_id.region->to_lowercase());
-        }
-    };
-
-    canonicalize_language(locale_id.language_id, false);
-
-    quick_sort(locale_id.extensions, [](auto const& left, auto const& right) {
-        auto key = [](auto const& extension) {
-            return extension.visit(
-                [](LocaleExtension const&) { return 'u'; },
-                [](TransformedExtension const&) { return 't'; },
-                [](OtherExtension const& ext) { return static_cast<char>(to_ascii_lowercase(ext.key)); });
-        };
-
-        return key(left) < key(right);
-    });
-
-    for (auto& extension : locale_id.extensions) {
-        extension.visit(
-            [&](LocaleExtension& ext) {
-                for (auto& attribute : ext.attributes)
-                    attribute = MUST(attribute.to_lowercase());
-
-                for (auto& keyword : ext.keywords) {
-                    keyword.key = MUST(keyword.key.to_lowercase());
-                    canonicalize_unicode_extension_values(keyword.key, keyword.value, true);
-                }
-
-                quick_sort(ext.attributes);
-                quick_sort(ext.keywords, [](auto const& a, auto const& b) { return a.key < b.key; });
-            },
-            [&](TransformedExtension& ext) {
-                if (ext.language.has_value())
-                    canonicalize_language(*ext.language, true);
-
-                for (auto& field : ext.fields) {
-                    field.key = MUST(field.key.to_lowercase());
-                    canonicalize_unicode_extension_values(field.key, field.value, false);
-                }
-
-                quick_sort(ext.fields, [](auto const& a, auto const& b) { return a.key < b.key; });
-            },
-            [&](OtherExtension& ext) {
-                ext.key = static_cast<char>(to_ascii_lowercase(ext.key));
-                ext.value = MUST(ext.value.to_lowercase());
-            });
-    }
-
-    for (auto& extension : locale_id.private_use_extensions)
-        extension = MUST(extension.to_lowercase());
-}
-
-Optional<String> canonicalize_unicode_locale_id(LocaleID& locale_id)
-{
-    // https://unicode.org/reports/tr35/#Canonical_Unicode_Locale_Identifiers
-    StringBuilder builder;
-
-    auto append_sep_and_string = [&](Optional<String> const& string) {
-        if (!string.has_value() || string->is_empty())
-            return;
-        builder.appendff("-{}", *string);
-    };
-
-    if (!locale_id.language_id.language.has_value())
-        return {};
-
-    transform_unicode_locale_id_to_canonical_syntax(locale_id);
-
-    builder.append(MUST(locale_id.language_id.language->to_lowercase()));
-    append_sep_and_string(locale_id.language_id.script);
-    append_sep_and_string(locale_id.language_id.region);
-    for (auto const& variant : locale_id.language_id.variants)
-        append_sep_and_string(variant);
-
-    for (auto const& extension : locale_id.extensions) {
-        extension.visit(
-            [&](LocaleExtension const& ext) {
-                builder.append("-u"sv);
-
-                for (auto const& attribute : ext.attributes)
-                    append_sep_and_string(attribute);
-                for (auto const& keyword : ext.keywords) {
-                    append_sep_and_string(keyword.key);
-                    append_sep_and_string(keyword.value);
-                }
-            },
-            [&](TransformedExtension const& ext) {
-                builder.append("-t"sv);
-
-                if (ext.language.has_value()) {
-                    append_sep_and_string(ext.language->language);
-                    append_sep_and_string(ext.language->script);
-                    append_sep_and_string(ext.language->region);
-                    for (auto const& variant : ext.language->variants)
-                        append_sep_and_string(variant);
-                }
-
-                for (auto const& field : ext.fields) {
-                    append_sep_and_string(field.key);
-                    append_sep_and_string(field.value);
-                }
-            },
-            [&](OtherExtension const& ext) {
-                builder.appendff("-{:c}", to_ascii_lowercase(ext.key));
-                append_sep_and_string(ext.value);
-            });
-    }
-
-    if (!locale_id.private_use_extensions.is_empty()) {
-        builder.append("-x"sv);
-        for (auto const& extension : locale_id.private_use_extensions)
-            append_sep_and_string(extension);
-    }
-
-    return MUST(builder.to_string());
+    value = MUST(result.to_string());
 }
 
 StringView default_locale()
@@ -775,15 +553,9 @@ ReadonlySpan<StringView> __attribute__((weak)) get_available_calendars() { retur
 ReadonlySpan<StringView> __attribute__((weak)) get_available_collation_case_orderings() { return {}; }
 ReadonlySpan<StringView> __attribute__((weak)) get_available_collation_numeric_orderings() { return {}; }
 ReadonlySpan<StringView> __attribute__((weak)) get_available_collation_types() { return {}; }
-ReadonlySpan<StringView> __attribute__((weak)) get_available_currencies() { return {}; }
 ReadonlySpan<StringView> __attribute__((weak)) get_available_hour_cycles() { return {}; }
 ReadonlySpan<StringView> __attribute__((weak)) get_available_number_systems() { return {}; }
 Optional<Locale> __attribute__((weak)) locale_from_string(StringView) { return {}; }
-Optional<Language> __attribute__((weak)) language_from_string(StringView) { return {}; }
-Optional<Territory> __attribute__((weak)) territory_from_string(StringView) { return {}; }
-Optional<ScriptTag> __attribute__((weak)) script_tag_from_string(StringView) { return {}; }
-Optional<Currency> __attribute__((weak)) currency_from_string(StringView) { return {}; }
-Optional<DateField> __attribute__((weak)) date_field_from_string(StringView) { return {}; }
 Optional<ListPatternType> __attribute__((weak)) list_pattern_type_from_string(StringView) { return {}; }
 Optional<Key> __attribute__((weak)) key_from_string(StringView) { return {}; }
 Optional<KeywordCalendar> __attribute__((weak)) keyword_ca_from_string(StringView) { return {}; }
@@ -794,57 +566,33 @@ Optional<KeywordColNumeric> __attribute__((weak)) keyword_kn_from_string(StringV
 Optional<KeywordNumbers> __attribute__((weak)) keyword_nu_from_string(StringView) { return {}; }
 Vector<StringView> __attribute__((weak)) get_keywords_for_locale(StringView, StringView) { return {}; }
 Optional<StringView> __attribute__((weak)) get_preferred_keyword_value_for_locale(StringView, StringView) { return {}; }
-Optional<DisplayPattern> __attribute__((weak)) get_locale_display_patterns(StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) get_locale_language_mapping(StringView, StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) get_locale_territory_mapping(StringView, StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) get_locale_script_mapping(StringView, StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) get_locale_long_currency_mapping(StringView, StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) get_locale_short_currency_mapping(StringView, StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) get_locale_narrow_currency_mapping(StringView, StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) get_locale_numeric_currency_mapping(StringView, StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) get_locale_calendar_mapping(StringView, StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) get_locale_long_date_field_mapping(StringView, StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) get_locale_short_date_field_mapping(StringView, StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) get_locale_narrow_date_field_mapping(StringView, StringView) { return {}; }
 
-// https://www.unicode.org/reports/tr35/tr35-39/tr35-general.html#Display_Name_Elements
-Optional<String> format_locale_for_display(StringView locale, LocaleID locale_id)
+Vector<String> available_currencies()
 {
-    auto language_id = move(locale_id.language_id);
-    VERIFY(language_id.language.has_value());
+    UErrorCode status = U_ZERO_ERROR;
 
-    auto patterns = get_locale_display_patterns(locale);
-    if (!patterns.has_value())
+    auto* currencies = ucurr_openISOCurrencies(UCURR_ALL, &status);
+    ScopeGuard guard { [&]() { uenum_close(currencies); } };
+
+    if (icu_failure(status))
         return {};
 
-    auto primary_tag = get_locale_language_mapping(locale, *language_id.language).value_or(*language_id.language);
-    Optional<StringView> script;
-    Optional<StringView> region;
+    Vector<String> result;
 
-    if (language_id.script.has_value())
-        script = get_locale_script_mapping(locale, *language_id.script).value_or(*language_id.script);
-    if (language_id.region.has_value())
-        region = get_locale_territory_mapping(locale, *language_id.region).value_or(*language_id.region);
+    while (true) {
+        i32 length = 0;
+        char const* next = uenum_next(currencies, &length, &status);
 
-    Optional<String> secondary_tag;
+        if (icu_failure(status))
+            return {};
+        if (next == nullptr)
+            break;
 
-    if (script.has_value() && region.has_value()) {
-        secondary_tag = MUST(String::from_utf8(patterns->locale_separator));
-        secondary_tag = MUST(secondary_tag->replace("{0}"sv, *script, ReplaceMode::FirstOnly));
-        secondary_tag = MUST(secondary_tag->replace("{1}"sv, *region, ReplaceMode::FirstOnly));
-    } else if (script.has_value()) {
-        secondary_tag = MUST(String::from_utf8(*script));
-    } else if (region.has_value()) {
-        secondary_tag = MUST(String::from_utf8(*region));
+        // https://unicode-org.atlassian.net/browse/ICU-21687
+        if (StringView currency { next, static_cast<size_t>(length) }; currency != "LSM"sv)
+            result.append(MUST(String::from_utf8(currency)));
     }
 
-    if (!secondary_tag.has_value())
-        return MUST(String::from_utf8(primary_tag));
-
-    auto result = MUST(String::from_utf8(patterns->locale_pattern));
-    result = MUST(result.replace("{0}"sv, primary_tag, ReplaceMode::FirstOnly));
-    result = MUST(result.replace("{1}"sv, *secondary_tag, ReplaceMode::FirstOnly));
-
     return result;
 }
 
@@ -852,12 +600,6 @@ Optional<ListPatterns> __attribute__((weak)) get_locale_list_patterns(StringView
 Optional<CharacterOrder> __attribute__((weak)) character_order_from_string(StringView) { return {}; }
 StringView __attribute__((weak)) character_order_to_string(CharacterOrder) { return {}; }
 Optional<CharacterOrder> __attribute__((weak)) character_order_for_locale(StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) resolve_language_alias(StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) resolve_territory_alias(StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) resolve_script_tag_alias(StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) resolve_variant_alias(StringView) { return {}; }
-Optional<StringView> __attribute__((weak)) resolve_subdivision_alias(StringView) { return {}; }
-void __attribute__((weak)) resolve_complex_language_aliases(LanguageID&) { }
 Optional<LanguageID> __attribute__((weak)) add_likely_subtags(LanguageID const&) { return {}; }
 
 Optional<LanguageID> remove_likely_subtags(LanguageID const& language_id)
@@ -902,21 +644,6 @@ Optional<LanguageID> remove_likely_subtags(LanguageID const& language_id)
     return return_language_and_variants(maximized.release_value(), move(variants));
 }
 
-Optional<String> __attribute__((weak)) resolve_most_likely_territory(LanguageID const&) { return {}; }
-
-String resolve_most_likely_territory_alias(LanguageID const& language_id, StringView territory_alias)
-{
-    auto aliases = territory_alias.split_view(' ');
-
-    if (aliases.size() > 1) {
-        auto territory = resolve_most_likely_territory(language_id);
-        if (territory.has_value() && aliases.contains_slow(*territory))
-            return territory.release_value();
-    }
-
-    return MUST(String::from_utf8(aliases[0]));
-}
-
 String LanguageID::to_string() const
 {
     StringBuilder builder;
diff --git a/Userland/Libraries/LibLocale/Locale.h b/Userland/Libraries/LibLocale/Locale.h
index ef0b445e98e..bc2ff37d736 100644
--- a/Userland/Libraries/LibLocale/Locale.h
+++ b/Userland/Libraries/LibLocale/Locale.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2023, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2021-2024, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -139,8 +139,8 @@ bool is_type_identifier(StringView);
 Optional<LanguageID> parse_unicode_language_id(StringView);
 Optional<LocaleID> parse_unicode_locale_id(StringView);
 
+String canonicalize_unicode_locale_id(StringView);
 void canonicalize_unicode_extension_values(StringView key, String& value, bool remove_true);
-Optional<String> canonicalize_unicode_locale_id(LocaleID&);
 
 StringView default_locale();
 bool is_locale_available(StringView locale);
@@ -150,19 +150,15 @@ ReadonlySpan<StringView> get_available_calendars();
 ReadonlySpan<StringView> get_available_collation_case_orderings();
 ReadonlySpan<StringView> get_available_collation_numeric_orderings();
 ReadonlySpan<StringView> get_available_collation_types();
-ReadonlySpan<StringView> get_available_currencies();
 ReadonlySpan<StringView> get_available_hour_cycles();
 ReadonlySpan<StringView> get_available_number_systems();
 
+Vector<String> available_currencies();
+
 Style style_from_string(StringView style);
 StringView style_to_string(Style style);
 
 Optional<Locale> locale_from_string(StringView locale);
-Optional<Language> language_from_string(StringView language);
-Optional<Territory> territory_from_string(StringView territory);
-Optional<ScriptTag> script_tag_from_string(StringView script_tag);
-Optional<Currency> currency_from_string(StringView currency);
-Optional<DateField> date_field_from_string(StringView calendar);
 Optional<ListPatternType> list_pattern_type_from_string(StringView list_pattern_type);
 
 Optional<Key> key_from_string(StringView key);
@@ -175,38 +171,13 @@ Optional<KeywordNumbers> keyword_nu_from_string(StringView nu);
 Vector<StringView> get_keywords_for_locale(StringView locale, StringView key);
 Optional<StringView> get_preferred_keyword_value_for_locale(StringView locale, StringView key);
 
-Optional<DisplayPattern> get_locale_display_patterns(StringView locale);
-Optional<String> format_locale_for_display(StringView locale, LocaleID locale_id);
-
-Optional<StringView> get_locale_language_mapping(StringView locale, StringView language);
-Optional<StringView> get_locale_territory_mapping(StringView locale, StringView territory);
-Optional<StringView> get_locale_script_mapping(StringView locale, StringView script);
-Optional<StringView> get_locale_long_currency_mapping(StringView locale, StringView currency);
-Optional<StringView> get_locale_short_currency_mapping(StringView locale, StringView currency);
-Optional<StringView> get_locale_narrow_currency_mapping(StringView locale, StringView currency);
-Optional<StringView> get_locale_numeric_currency_mapping(StringView locale, StringView currency);
-Optional<StringView> get_locale_calendar_mapping(StringView locale, StringView calendar);
-Optional<StringView> get_locale_long_date_field_mapping(StringView locale, StringView date_field);
-Optional<StringView> get_locale_short_date_field_mapping(StringView locale, StringView date_field);
-Optional<StringView> get_locale_narrow_date_field_mapping(StringView locale, StringView date_field);
-
 Optional<ListPatterns> get_locale_list_patterns(StringView locale, StringView type, Style style);
 
 Optional<CharacterOrder> character_order_from_string(StringView character_order);
 StringView character_order_to_string(CharacterOrder character_order);
 Optional<CharacterOrder> character_order_for_locale(StringView locale);
 
-Optional<StringView> resolve_language_alias(StringView language);
-Optional<StringView> resolve_territory_alias(StringView territory);
-Optional<StringView> resolve_script_tag_alias(StringView script_tag);
-Optional<StringView> resolve_variant_alias(StringView variant);
-Optional<StringView> resolve_subdivision_alias(StringView subdivision);
-void resolve_complex_language_aliases(LanguageID& language_id);
-
 Optional<LanguageID> add_likely_subtags(LanguageID const& language_id);
 Optional<LanguageID> remove_likely_subtags(LanguageID const& language_id);
 
-Optional<String> resolve_most_likely_territory(LanguageID const& language_id);
-String resolve_most_likely_territory_alias(LanguageID const& language_id, StringView territory_alias);
-
 }