I think you have cause to be concerned. You said he gets speech therapy. Has there been any comprehensive evaluation done by a team of educators (Special Education Teacher, Speech Therapist, Occupational Therapist and Psychologist)?
Another couple things is that he never asks any questions like they do at that age my 4 year old son was always asking how?, Why Where but he never does except for one question that he ask everytime we pass it. Is that your gym? He asks this question everytime we passmy gym on the way to work. He has other things that he always does as soon as i start cooking he always says/asks is tea ready? One more thing he does everyday is when i ask what he wants for his bedtime snack he always says wait and see and he has to come pick it although he knows exactly what he can have. All this may sound strange put it loads of small details that all add up for me to worry the kind of repetitiveness.
Thanks for taking the time to read thia and sorry for going on and on