I've wondered about Sesame Street for a few years now. My only recent exposure has been through their video/DVD offerings, viewed in the company of my nieces. One character, Baby Bear, speaks poorly in that he uses W sounds in place of R sounds. My brother and I both frown at that one, since it seems counter to everything we thought Sesame Street was trying to do. Yes, very young children might have trouble distinguishing that sound, and take a while to get it right. I don't think they should be showing an example of how not to do it, though.