Teach him a word, phrase or action to replace the screaming and screeching. For example: Say: "Instead of screeching, say: "Whoohoo!" (Whoa! Yahoo!) any word you consider an acceptable alternative. Remind him of his new word. The intention is...he can't screech and say this new word at the same time...so the appropriate response should replace the inappropriate response. The same goes for screaming when upset. Instead of screeching, teach the child to express their disappointment by saying something like: "Oh man!" Remind him each time he screeches. "Remember! Instead of screeching, you should say _________." Encourage him by saying these alternate words every time something "exciting" happens. Reward him when he does it correctly. Good luck.

I agree. My son used to squeal constantly! It is one of the most annoying (yes annoying) behaviors I find.People always say he 'can't help it', but now that he can communicate appropriately (first with PECS, official, now with verbal words) there is little squealing and usually with a prompt replaced with words. I think it is all about the words. So modeling back (in a whisper) some happy/excited phrases and really expressive facial expressions may help. Really praise/reinforce (even with tangible items...token system of some type might help) for quiet voices, good words, ect. good luck1

You can also reward him when he is quiet or using a quiet voice, but you have to be consistant in rewarding him. Say "I like how you are being quiet" and give him the reward immediately. Use a toy, food or favorite item that you will only give at this time and only this time. Don't give a food that you will also use for dinner or snack or it will not be affective. This is an ABA rule for trying to reward for good behaviors.

When my son is doing something that is not appropriate (screaming, scratching, hitting, biting) I bring attention to it by saying "What are you doing" He will answer and say "Screaming" I then say "Is that Ok" And he says "No" Then the behavior stops. If your son does not yet have the language to do this. Still say it and model the answers. And as always be at eye level. Be stern but do not yell.

This could be a hearing/sensory problem. A speech therapist may be able to help too. We used PECS at our home to help give our child a way to tell us what he wants. That calmed most of the screeching. Now he only does when he is excited.
I liked some of the other comments about something that vibrates. You can find basic ones in the store for under $10. Like a small hand held one that is used to massage your back or neck (nothing s..ual). My son loves it and loves to have it on his back.
Oh and the Hex Bugs that you can buy from Target, they are really good too and you can get a small one for around $5-$6. These are nice because then your child can play with it too as a toy. They do make special vibrating toys for kids with Autism but they can be pricey depending on what you get. Here's one that is cute

http://www.autism-products.com/ProductDetails.a...