My Butch, who is 5 months old ... used to bark alot when I first got him... he's stopped (unless there is something he wants). He is really good.. he knows what "no" and "stop it" means....
My Bitsy, who is 4 months old ... she still nips when she plays... but I notice it is not as severe as when she was real young (she's from my Pebbles' last litter so I've always had her).
They do eventually calm down... about a year old.
Good luck!!