The article I posted doesn't really make that clear--that hyperlexia is reading without comprehension. I think in a really young kid, esp. one w/ expressive speech delays, it can be hard to know if they are comprehending. So maybe your DS was actually not hyperlexic. He does sound very similar to my DS and all I can tell you is that his reading has stayed advanced at age 9. I think he had very early reading ability and he was an excellent decoder, but he was never truly hyperlexic.