The feature will get a dedicated location in Settings -> System and will apparently support 55 different languages to varying degrees, most of which it will only support in a limited way via the camera. According to the list published, only Spanish, Portuguese, Japanese, Italian, German, French, and English will get particularly good support for Live Translate's various features.
Trying to download a Portuguese language file to use with live caption translation on Pixel 6, but I can only see: French (already installed so you can't see it in the screenshot), German, Italian, and Japanese.
I recall I saw on some forum that Portuguese is also an option. Does anyone know more about this?