He is at the phase in life when he repeats things you say and is always on the go.
Just real quick, here are some of my favorite sayings of his:
Q: "What does Buzz's helmet do?"
His Answer: *Whoosh! and moves his hands up over his head*
Q: How old are you?
Q: How old is daddy?
What does a werewolf say?
What does Woody say?
What does mommy say?
Love you mommy.