I understand your fear, because I experienced the same with my ds3 now almost 6 year old. As a baby he had many ear infections and couldn't hear well most of the time. He began speaking at five months, but he would speak for a month or two, then regress. I read a LOT to him. I showed him flash cards saying each sound slowly and clearly; I was trying to get him to talk. Ds2, two years older, began reading at 2yrs, 3months, and I taught phonics to him with ds3 sitting or nursing on my lap. One day, he was 23 months, he picked a homemade phonics book that belonged to ds2 and read every word, 460! From then on, he read everything he could get his hands on, provided the font was large. His pediatrician became concerned with his behavior, he wanted to read and count all the time, and played very little with other children. With close observation, we decided he was fine because he was emotionally responsive at home. ds3 took time to socialize well with other children, basically after his hearing became normal; by age four. Anyway, he is almost 6 now, and he reads at a seventh grade level, though we use reading comprehension at a sixth grade level. His math ability is also excellent, we use Singapore math, and he is currently doing 4a, we supplement with ALEKS, and he is social, active in sports, and a well rounded child. I advice you to observe his social responsiveness at home, and if it is normal, then don't worry! Also, read to him and let him advance at his own pace, no matter how fast! As a side issue, my ds2 learned to read after 2, and he was tested by Sylvan at 7yrs, 4months. His reading tested at a ninth grade level, and his math at the 12th. He was given form 20, which is the same test given to tenth grade high school students. I'm homeschooling my boys and they seem to complete a school year every 3-4 months.
