I have a friend with 2 greys. She is always telling me what noises they are imitating now! The latest one is water dripping from the faucet. Hannah is starting to imitate me, I guess I "cluck" at her a lot. Can't think of a better name for it than that. She will do that and say "c'mere". And she is so funny, she will say "step up, step up, good girl, gooood girl". She is trying to say more things all the time.
Good luck in your search for a grey. Buy the biggest cage you can afford, you will be happy that you did so later!
Connie in Oklahoma