Java already has this option and as someone with a hearing disability I find it to be essential. Without subtitles I feel handicapped and it’s a horrible experience.
I would personally rate this as being critically important accessibility-wise. Playing Bedrock for the first time for the Movie Live Event and I didn’t know what was around me or around the corner, so had to keep turning to look, I was lucky that I was on my computer as turning is easy but on console with a controller if you are unable to listen you also can’t really quickly turn around to have a peek, so the game would be impossible to play on par with someone who can hear - on Java I’m as capable as someone who can hear because of the subtitles.
I searched before posting and didn’t see it be mentioned before on here. Just on the old site, which it wasn’t clear was actually still active