That's a really good solution - from memory a similar system is used on the headsets worn on Sydney Harbour Bridge tours. I'd forgotten about them until you mentioned vibrations.

I'm actually going to be disappointed if they don't have this in some form. I guess the most elegant solution would be to read skull vibrations rather than use voice at all - I'm not sure how viable that would be though.

That's not for voice recognition, it's to replace the headphone SPEAKERS because it's so windy on the bridge. The thing sits on the bone just in front of your ear. It's a really funny sensation but works well.

But I assume the same system would work in reverse.

I know that the bridge headset replaces the speakers, but reversing the system would remove a lot of the inherent problems with a system that relies on speech for input.

I remember using them when I was on the Harbour Bridge what feels at least 5 or 6 years ago - so maybe the tech has developed enough since then. Especially if Google has been throwing resources at it.