There's not much Cooper has done so far to mimic us. I keep waving "hi" and "bye." I even try some sign language at feeding times - more, all done, hungry? I think he understands hungry, but only when I say it. I tell him "mama" and "dada" all day long, only to get a loud shriek in return. (Oh, he's got the shriek down pat - sometimes we have shrieking contests when it's just Cooper and me around.) I do think we caught him clapping a couple of times but not really in response to us.
And then yesterday it happened - he started mimicking... THE DOG! Yes, I caught him barking. You may not believe me, so see for yourself. It goes like this: Cooper and I are playing upstairs. All is quiet. Roscoe begins barking. Then I hear a faint "ah ah ah ah ah" from Cooper. Over and over and louder and louder until Roscoe stops. I think, "well that's unusual. Surely he's not doing that because of the barking." But then it happens again. 10 minutes of silence from Cooper and all of a sudden Roscoe starts barking. And so does Cooper. Huh. What do you think? World's cutest barking baby? I think yes. :)