8yr son repeated episodes twitching jumpy chewing in sleep couldn't wake him in morning went hospital he said he couldn't move or talk no answers why?

Several things poss: What does your pediatrician say? Getting a pediatric neurologist to take a look at your son would be a good first step and then, they could potentially refer him for a sleep study or other diagnostic testing to identify either the type of sleep disorder or other problem he may be having.

See a neurologist: Your child should see a neurologist. It is possible that he has Rolandic seizures.