Dog doesnt bark

Question
Why doesn't my lab bark?   I purchased my lab when she was only 12 weeks old, she is now 2 years and 2 months old. She doesn't bark.  I need help,she won't let us know she has to go to bathroom and she can't even bark if someone is at the door.  When she see a stranger she run up to them and roll over on her back and asked  for a tummy rub.  What the hell is wrong with my dog???.

Answer
You can teach your dog to speak on command, but she still won't bark at ppl outside unless you also teach her to do that.  To teach her to bark on command, you "frustrate" her.  Is she food driven (probably a stupid question since she's a Lab)?  Hold a piece of kibble or a treat in front of her.  Let her know it's there and get it close enough that she thinks she might get it, but don't let her have it.  After you literally tease her enough, she'll get fed up and will most likely bark at you.  Once she does that, she gets the treat and you say "good speak".  Repeat, slowly fazing out the treat and fazing in the command.