Training Dog to Speak?

I'm trying to get my dog to learn how to speak. It seems like he does everything I ask but speak. He can sit, stay, lay down, beg, jump, dance, roll over, and shake. He's a labrador retriever and he's very quiet, unless my other dog Daisy barks at someone, then Dexter (my dog) barks too. I've tried getting Daisy to bark so he will, but he still doesn't bark. Any tips or ideas to train Dexter how to speak? I don't want to go to obedience class because I would have to drive two hours to get to the closest class.