I'd very much like to see this for future LIVE letters, however I do see devs hesitation to do so, since if they provide an english translator they'd have to add a french and german one too otherwise those communities would cry foul. I think a good balance would be to have seperate audio for each localization setup with translators speaking off camera for their respective languages.

What I'd enjoy most though, would be if LIVE letters were pre-recorded and had subtitles. They'd still be recorded "live" we just wouldnt be seeing it live.