What worked for me and the therapists is floor time, tons and tons of floor time. Play, play, play. from cars, to stories and even eating. At 4.5 my son had his first word and now at 7 he is speaking in full sentances. the more time you spend at his level the better. Be as dramatic as possible when you speak to him. BIG emotions. I meand DRAMA. " The car goes VROOM....and smashed into the (pile of cotton balls) SNOW". Throw the "snow". then do that 10 more times. Even when playing the more expression you put into it the more they take from it.

If you have tried signing, use the symbol for "more". each time he takes your hand to play, say and sign "more". he will catch on pretty quick if you stop every 2 mintues, say and sign more. Once you have signed and said "more" for like the 100th time, just sign "more" and ask him to say it. You may have to do this 100 times more but he will then demand it. the more he demands, the more power you will have to coax words.

If I can pass on anything to you - use paper plates, dont worry about the mess, take time to play. Good Luck!

My child is deaf and non verbal. We came across DVD signingtime. It has worked wonders. Until these DVDs he had no way if communication nor did he want to do anything else. I know you said sign doesn't work but try these. They even have an autism bundle. You can also check out at library for free. My son and I know 80 words and the DVDs are real people so he can relate. And we use them for everything. In beginning start off with the child's "wants" more .... Drink. iPad. Etc. I wish you luck. I know how upsetting it is to have a non verbal child.... My son still needs to know a lot more but we are getting there

Use an app to comunícate like Pecs system but in a tablet. I have used the app LETME TALK and now I'm using Proloquo2Go .

Try the Baby Einstien signs DVD My grandchildren loved it and it helped them to learn basic signing.DIR floor time is excellent too. Make play time goofy and fun so you can keep their attention.