Enter Hacking Autism. If you can watch the one mother saying her child spoke to her for the first time in 15 years and not burst into tears, you are stronger than me.
Click on the left side where it says APPS. These are designed to help unlock language in people with autism. My sister understands everything we say to her. She simply cannot talk to us. The reason why is the mystery (and maddening frustration) of autism.
If this can help anyone you know, you should send it along. It's always a good idea to put more tools in your belt, you know?