That just tells it which languages to serve if the video has multiple tracks, including Ai-generated ones. "Keep original language" should be the default, or at least an opt-in.

And what about the atrocious title auto-translations? I'm in France, my browser is set to accept EN-us and FR-fr as languages, and my Youtube is in EN. And yet it keeps auto-translating the titles of some French videos. And the translation is so awful, it mistranslates many things and translates literally some obvious puns, that I can't believe they're using Gemini for this. They must have repurposed a 5-year old version of Google Translate. It is not consistent either, the titles are translated in the home page, but not in the channel's page.