If your son is not responding on being called then he is either having some degree of deafness, or he is simply not paying attention, as one may encounter in ADHD. Poor hearing may be the reason for not being able to speak. I would get him tested for his hearing first.
In autism children usually do not mix with strangers , but he plays with kids so it's less likely.
Answered2015-11-03 11:42:18
Let others know if this answer was helpful