Ubuntu did that too for a while. I had a kubuntu cd.

Check whisper apk on fdroid. The thing runs local. It does just this. The model gets audio in an undetermined language, figures out which one automatically, transcribes it, translates it to English (only English atm) and then it speaks it out. It’s not using any acceleration and its a very early build. My Pixel 9 is getting about 3 seconds delay from input to output. It’s all running local.

It’s doable.

If you’re concerned about these kind of things, you might want to know about the GrapheneOS duress password. You set a second PIN, called duress PIN/password. If you’re ever forced to type a PIN, you can type this one instead of the real one. It will lock/wipe out the phone within a few seconds. There’s a few youtube videos showcasing this self-destruct mode.

You might want to consider your next phone to be a pixel+grapheneOS.