Time was, extra language codes for Wikidata labels were added by adding them to the wmgExtraLanguageNames in the wmf-config/InitialiseSettings.php (for the wikidata dblist and later also commonswiki). This was bad for several reasons, and so we eventually moved that configuration to Wikibase (T260118: Move content of $wgExtraLanguageNames on Wikidata to default Terms languages). However, soon afterwards we added the wmgExtraLanguageNames back to the production config (T264295: Reinstate $wgExtraLanguageCodes in production). We would like to remove it again to avoid confusion and issues – for instance, T272242: Language code "dag" for Dagbani does not work for lexemes happened because the language code 'dag' was added to the Wikibase list but not the wmgExtraLanguageNames.
Removing the production wmgExtraLanguageNames is blocked on at least two tasks:
- T124758: [Story] Show all available languages in monolingual text value's suggester. This is the original reason we reinstated wmgExtraLanguageNames: without it, those additional languages are harder to use.
- T273625: Make lexeme language codes inherit from Wikibase default terms languages, not MediaWiki content languages. Language codes like kea, nod and ota are currently only available for Lexemes on Wikidata because they are in the wmgExtraLanguageNames – they’re also in the Wikibase language codes, but WikibaseLexeme currently doesn’t use those. If we remove wmgExtraLanguageNames before T273625 is done, then those language codes will become unavailable for Lexemes on Wikidata.