<<Of course I may totally be missing your point. It just seems that Aspergers kids are susceptible to language delays, and according to the book, he is at the right age to begin a language explosion?>>
My son did not speak more than 4 words at age 3. We went to speech therapy at first at 2.5, then really go into it at 3. When he did start speaking, it was wild! He could name every dinosaur he could get his hands on, but still wouldn't communicate with us. He was about 4 or 4.5 before we really started getting him going. And then...whew....watch out! We are still "humans" and have "nice vegetation" or "foliage" in our yard....not grass and trees. He sometimes sounds like a little alien speaking
He is very at ease with adults and will really chat them up. When he went in for his neuropsych, the dr talked to he and I for about 10 mins, and then her assistant took him for testing, while we finished the parent interview. She assured me it wasn't Asperger's right then and there. She called me 2 weeks later and told me there was reason she never said never...hehehehe......his results came up Aspergers!
I really didn't start to notice how 'odd' things were with my ds until I had ds #2, and he was reaching milestones his brother hadn't even yet, eventhough they are 3.5 yrs apart.
So, just having more language delays than is 'usual' for Asperger's I don't think necessarily rules it out. From what I understand, it is a spectrum...and every AS kid will look a little different!
We were hot on getting a dx, as we didn't need one for IEP reasons, but our insurance kind of wanted to know WHY they keep paying for services on this kid! And, then there was 'showing' my ex-dh that there really was something to all that we were up against with him, that it wasn't just him misbehaving.
But, as khrisday said....whatever label gets you the services your son needs is helpful!