Q. "Any tips or hope for those of us who have been doing all of the above for years with little result would be great."
A. As a parent who was unable to accept the fact that years and years of speech therapy were not giving my son a voice (he wasn't making any real progress), I think it's so important to have an open discussion with your speech therapist and developmental pediatrician about what is realistic for your child.
If I could do it again, my goal would be that my child spend the majority of his time in activities that bring him joy and where he can be successful.
My son couldn't be successful in speech.
But he was able to communicate more using sign language, pictures, voice technology and a computer. I think you need to assess, with the help of a professional, which mode of communication is most possible for your child, and make that the focus. As parents, we get too hung up on speech. If your child isn't making meaningful progress in that area, take another route!
Perhaps other readers can offer their suggestions? Thanks, Louise