I have a co-worker who speaks unbelievably quietly. Rather than constantly asking him "Huh?" "Pardon?" "What did you say?", or pretending i heard him, it'd be nice if i could get subtitles that tell me what he said.
The minimal set-up for this device would be a sensitive microphone, embedded computer
and on-glasses projector HUD. For more accuracy, i could get him to carry his own microphone, that would talk to mine via some radio thing.
It wouldn't need to be 100%. Generally, a couple of words per uttering is all i'd need. You could even use it to 'record' conversations and go back a few minutes to see what somebody is talking about.
You could, of course, use this in loud bars, or for talking to foreign people. You could also lock out people that you don't want to hear you. People who don't use glasses are left out, of course, but i don't think it hurts for us to have an advantage over them.