Saying Thank chu (you)

It was just another day. As usual, we were playing and Richie expressed that he was hungry. I brought and gave him his favorite choco biscuit. He said "more biscuit", "2?". I gave him one more. And he said "Thank chu". O' wow!! He could say without anybody instructing him to do so.

and btw he also says "Oh Wow" and puts his hands to his mouth if he likes something very much. ;)