It's funny that on our 'phones' these days we do little talking. It's also funny that although we could just talk to someone with the phone, we choose to text them. I do it too. For lots for reasons, but the one I'm thinking about right now is that it is quiet, and therefore somewhat private, and you can text in lots of places where talking would be inappropriate (like meetings, presentations, etc.)
But boy, typing on these smart phones is not a great experience. The finger size-to-key size ratio is just too large.
I sometimes use Siri as speech-to-text entry, but again, you're limited by places you need to be quiet, and by places that are too noisy.
So, wouldn't it be cool to use that 'selfie' camera on the front of the phone as a lipreading text input? You'd get your lips in focus, and then breathlessly mouth the words, and watch the words appear in the text window.
Would it look weird to others? Yeah. But they'd get used to it, 'cause they'd do it too.