M.C.
Boys are slower at developing. As long as he makes eye contact and moves around, I would not worry so much. My first son walked at 9 mos but my 4th son was 15 mos before walking. My 5 year old did not talk until he was almost 4 and my 2 year old talks all the time. Just relax. As long as you don't see any muscular problems, he will eventually catch on.