Problem: Many language names do not have translations in MediaWiki. Wikidata, Commons structured data and the {{#language:...}} syntax often fall back to English instead. Translations cannot be easily added.
Proposed solution: Language names should be translatable on translatewiki.net. The CLDR data could be used to provide the initial set of translations so that only missing names need to be translated. Updates to CLDR could be used to update unedited translations and add translations that are missing.
Who would benefit: Speakers of languages other than English.
More comments: MediaWiki fetches translations of language names from CLDR. CLDR does not support all languages that MediaWiki supports and does not have (and does not intend to have) translations for all language names. The LocalNamesXx.php files can only be edited by submitting patches.
