Why is Mia talking to her hand?

Yeah, that's a puzzler. She holds her hand up in front of her and just babbles to it. We think it's cute (of course, everything she does is cute). We asked her speech therapist about it, and she was interested. She said Mia might be starting to play pretend and that the hand might represent something outside of herself that she's talking to. She suggested we get her some hand puppets. Anyone else out there whose kids spoke to their hands? The mind of a child is wondrous to behold ...