Localisation

Studio handles it in the Subtitles section: set the original language, add a target language, then supply a translated title and description alongside the captions. Viewers using YouTube in that language see the translated metadata in search and on the watch page, which is what they read before deciding whether to click.

Machine translation gets you started and rarely finishes the job. A title translated word for word usually loses the hook, and an idiom translated literally reads as nonsense, so the languages worth doing properly are the ones already showing up in your audience geography report. Alternative audio tracks are a separate feature from translated text.