Yes, thanks. Very helpful.
I also chose Wi-Fi For the same reasons you mention.
True, it does not work over the Internet, but what I have found is that it does work in some stores (for example, grocery stores, hardware stores) where the two people are positioned at opposite corners of the store, way more than 30 feet apart. The IP addresses of both devices are on different subnets, but the in-store routing tables must have routing paths defined between the subnets. It still works.
I found the same thing with Google's cloud solution. With Microsoft Bing they allow 5000 transactions for free, but doing continuous VR will eat that in no time.
Thanks for the CMU Sphinx info. I had just played around with that a little bit. I think the latest version at the CMU website is 5 Alpha. It's probably not quite ready for prime time.
If you are interested in taking a look at the first version of my solution, search Google Play for Deaf Chat. It's from CanalRun. I think Google Play, at least in the USA, gives you a generous amount of time to play with it, if you don't want to keep it.
Barry.