Speech processing is a secondary issue. Others are working on it, and it's basically a solved problem for the most part.

I don't know about SQL's natural language support, so I won't comment.

As for languages, the technology is independent of particular languages, so you can in principle add modules for, say, core Mandarin vocabulary, and then write your apps for Mandarin. I only speak English, however, so I can only add core vocab for that. :\