It's great that you picked it up so young, daydream. He has the best chance for improvement. I learned makaton many years ago when it was used with IH patients and was surprised when I heard a couple if years ago that it was back in vogue. Even now hubby and I signal simple things to each other if it's too far to talk.

This is in no way connected with your situation, it was just something I read the other day and found interesting.

http://theconversation.com/were-not-talking-to-our-kids-are-we-causing-speech-delay-23585