My 4 yr old son doesn't listen and won't respond when we talk to him, he is very smart and know his alphabet and his numbers but won't listen and doesn't talk at all only sometimes and its hard to understand him. What can I do ?

Children who can't hear, can't learn the spoken word. You may have to make an appt. with his pediatrician to get a referral to a specialist for testing to get to the bottom of the problem. Which may be a hearing problem. Especially before he starts school. This has nothing to do with his aptitude and being intelligent, he just may not be able to hear.

Has he had a history of ear infections ?