I say don't stress too much! As I have quickly learnt from this site - all babies are so different. Some are noisier, some crawl earlier, some have more teeth, some eat more, they are all individuals and I wouldn't be too concerned. My daughter is 9 months old and babbles a bit, but not that much either. I am sure he will make up for it one day! Just think, if they were all the same life would be a bit boring wouldn't it?