"What That?"

This morning we were reading the book, Brown Bear, Brown Bear What Do You See?, one of Madeline's all time favorites!  We have read it about a hundred thousand times.  We got to black sheep, black sheep and she flipped the book back two pages.  She looked at the picture and said, "what that?"  I said, "that's the purple cat."  She said, "ooooohhhhhh." as if she knew, but had just fogotten.  Then I realized, she doesn't know how to say, "what that" and I started cracking up.  This girl is a great communicator!