What That Mean??

This phase has become dear to me. Brandon has been using it a lot lately. It used to be that if he didn't understand what you were saying, he would just let it go and say nothing. Now he is asking "What that mean". This morning I have heard it twice. Once when I said I expected him to behave in math today. His reply was "What that mean - espex". I then signed that I wanted him to behave and then used other words until he said OK. Later he brought me a dollar and asked "What that mean - washington". I then showed him the man and told him it was his name. I think it's a big step for him.