Verbal Maturity

I'm amazed everyday at how quickly we humans develop from babies into children and then adults. Lately when I ask Adam a question, i.e. "What do you want to play?" he replies with "Ummmmm, blocks!" The answer to every question always starts with an 'ummm' which to me means he is finally starting to understand how to make a decision.
His other new thing is if he is asking for something and says "Adam want phone" I will repeat what he says just to verify what it is and instead of saying 'yes' he says 'Oh', but with a Fonzie (from Happy Days) tone to it. It's really funny! Everytime he does it I laugh out loud at him!
I have no idea where he gets some things from. Yesterday he started singing "happy birthday..... to adam" the WHOLE song!