My youngest child had a speech delay. We enrolled her in a two hour class twice weekly specifically for children with speech delays when she was 3 yrs. old. It was recommended that we described every movement, activity and thought aloud...which feels a little funny in the grocery store, etc. However, after 3 yrs. of speech therapy (completely free through our local public school system, I might add) she tested out and graduated the program last month. Progress was slow, but steady. I would recommend NOT teaching your son sign language until you note progress in his speech, however, as I have witnessed a child's tendency to rely far more on signs and losing motivation for spoken language. While frustration is painful for both your child and for you, it can also be a great motivator. Lots of eye contact and hugs.