J.
Try doing something that may slightly startle him when he does it, ie: making a loud noise in lieu of saying no-no or something along those lines - WHATEVER YOU DO - Do not bite back! That is the worst advice, but for some reason there are some people who will prob offer it. That just reinforces the behavior. Good luck- And though it may sound trite, it really probably is just a phase, just be consistent above all else!!!!