DS4 was obsessed with books from about age six months on. (I have an amusing anecdote that I've told here before about that and a daycare worker who just couldn't calm him when she worked with him.) We read to him a lot, and at 3.5, he started reading back. He's all about Captain Underpants and Ricky Ricotta right now. He would still rather have us read them to him than read them on his own, but he will spend an hour at a time leafing through them. He's going fast enough that I think it's unlikely he's actually reading, rather than just looking at the pictures, but I don't know for sure.
Leafing through a book for an hour at a time is great. I bet he is reading more than you think. There have been many times DD has read a book seemingly too fast. But, her retell was great. And, on closer examination, her little finger traces the lines and her lips move silently. You would be surprised by how much faster kids can read in their head at this level. They may be glossing over a word every now and then, but if they are enjoying the books, I think it is OK.
