Hi H.,
I, myself, was born with a hearing loss, in which, my parents did not find out 'til I was 3 - 3 1/2 years old. Up until that time, all I would do is point & make sounds at things I wanted. I didn't learn to talk until I was fitted with hearing aids. Both of my daughters, whom are almost 2 1/2 & 4 years old, have normal hearing. I also have a cousin, whom, we told my aunt when she was 18 months old, to have her hearing tested. As it turned out, she too was born with a hearing loss. Does he respond to you at all, are you able to get his attention or does he just stare off into space. When you do get his attention, are you talking extremely loud or in a normal tone of voice. I'd like to tell you, to please, if you have not already done so, to have your son's hearing tested. Go to an Audiologist & have him tested. The sooner you know, the better off he'll be. Also, he may just be ignoring you as most 4 years old do at that stage, which, he'll outgrow.