Both of my children made tremendous progress and they both developed speech through the implementation of Applied Behavior Analysis.  Specifically, we implemented Verbal Behavior, based upon the works of B.F. Skinner.  VB focuses on the aquisition of speech and the application of errorless learning.
It is said that if you don't know someone living with autism, you will soon. Just What is AUTISM?
HOW B.F. SKINNER TAUGHT HIS CAT TO FLY First a crouch, Then a spring, Then a pounce, Then a leap. Add a flap And a glide And a soar (Not too steep). In the air Look around. Now you're up! Don't come down. -Ernest M. Schuttenberg	The B.F. Skinner Foundation http://www.bfskinner.org