Really interesting program, although, as Andrew has said, seems kinda limited. That's not your fault at all; any early project will seem limited in scope. Given some popularity and extra effort, something like this could be the Siri of the command line. Which gets me thinking -- is stuff like Siri and Google Now really just like this? Core set of pre-set commands surrounded by regex magic to recognize said pre-set co…
Anyway, it does seem that most proof-of-concept voice-control (as opposed to text-controlled) systems use a prefix too "siri"/"glass"/As for you question, I think it should be relatively easy to train, say a music-player app to understand stuff like "next song", "accept call", "repeat" -- in any language, using simple statistical methods. Not sure how far you could take it though (example, dictation software still makes (AFAIK) enough errors that it's not really a viable option if the user already can type reasonably well (or hire an actual stenographer)).