While generally I agree with you Crayola Kiddies, I'd be mindful of being too harsh too fast - gently encourage her to say "please" when she wants something, but don't force it to the point where she gets super-frustrated. I only say this because my own daughter didn't start talking until just past her second birthday, and she used to get extremely frustrated when we were asking her to say a word and she just couldn't seem to get her mouth to work the way she wanted it to - it resulted in colossal tantrums and freakouts. Eventually she caught up, but for a few months she was very upset whenever she kind of "clued in" that she couldn't yet say everything she wanted to.
I also have a 2yrold dcb who ONLY says mama and dada, and is at this point very obviously in need of some speech therapy and an overall assessment (which he is finally getting later this month! yay!) as he has pretty severe eating issues as well. With him, trying to make him talk would get absolutely nowhere, he makes no attempt to use words, and only says the consonants "ba" and "boo," no other sounds.
I guess my point is to just make sure they are capable of using their words before enforcing it too strongly, because for my little dcb at least, he simply can't, and I don't want to cause more grief for the little guy. Once they've started, for example, you got them to say "please," then you know it's just a combination of laziness or lack of confidence or taking the easy route by grunting, then go ahead and let them know that they need to try the words-just establish (or try to) that there isn't something more serious going on first.