Bailey was 14 weeks yesterday, and my wife has taught her to "Speak" on command. Personally, I'm already thinking a more practical command might be "Hush," but we'll be working on it.
I've assumed that she's just now getting to a trainable age, but I might be wrong. I know PetSmart will accept puppies for their kindergarten class as early as 12 weeks.
We've worked some on "Sit" and during a 10-15 minute session she will seem to be catching on - but the next session it seems like we're starting from scratch again. "Come" is intermittent right now, too. She's more likely to just come running as soon as you say her name as she is to respond to "Come."