Live closed captions (text only) is very common and standard. Usually those are done by an external company listening in to an audio feed, and sending the data back. It used to be done with regular POTS lines and telnet, but now it’s obviously more common to use public internet based services like EEG iCap[1]

I don’t know too much about it but I had read recently that ASL sign language can be thought of as a different language, rather than a direct equivalent to text subtitles[2].

[1] https://eegent.com/icap [2] https://imanyco.com/closed-captions-and-sign-language-not-a-...

> I had read recently that ASL sign language can be thought of as a different language

Yes, it is a different language. I've heard that ASL is rather similar to French Sign Language and quite different from BSL (British Sign Language). If someone were to translate something from English into ASL, and someone else were to translate the ASL back into English, I'd expect the result to be as different from the original as if they'd gone via some other language, like Italian, for example.

There's a variety of running jokes that Italian is half sign language anyways.

(Apparently derived from the fact that in Italy, there's quite a lot more non-verbal communication with hand gestures than other parts of the world)