My second child, a girl, was not talking at that point either with the exception of a couple words. Her problems stemmed from chronic ear infections that resulted in doing the surgery to have tubes put in at 2 years. While she did not have a measurable hearing loss, they determined that the fluid in her ears was just causing things to be muffled. Through speech therapy that started at 2, they realized she was missing some middle sounds and some ending sounds to words that took her a while to pick up again correctly. She had no trouble at all understanding anyone talking to her and had her own grunts and signals for what she wanted to say.
I did not read every post response here but I do just want to make a point. Even though your child may not have any other issue than he is just not using words yet, speech therapy is a wonderful thing. We have early intervention services here in Pennsylvania which is what we choose to use versus private (and expensive) speech therapists and the program is wonderful. Speech therapy at such a young age is not an aggressive, "horrible for the child" thing....my daughters initial year of therapy was done in our house and then at a local school. It involved a lot of play and just getting her to use and repeat sounds as she played. She loved her therapists and looked forward to seeing them each week, mostly because she wanted to play something new!
She is now in first grade. Her therapy transitioned last year with her into school and she continues to progress leaps and bounds. She now is only working a few isolated things and is completely understandable to all her peers and teachers, which wasn't the case two years ago. After this year, she will have met and surpassed all the normal speech developments for her age and will not have to continue with therapy.
I have heard over and over from her preschool teachers and now her grade school teachers how valuable it is to begin speech therapy if you as a parent or on recommendation from your doctor feel its necessary. My feelings were why wait and hope that it works itself out. I did not want her to reach school age and still have difficulty communicating. She was so much more confident and so much less frustrated when people, including us as her family, could understand what she needed and wanted to say. She has peers in her class that should have had therapy before school and did not until they entered school, and its amazing the struggles they are now having.
My sister-in-law has just started her third child, a boy who is 19 months, with the same program because he does not say anything either but again has no trouble with the hearing or understanding. She also is so pleased with how he is responding to the therapists and is glad she followed her gut feelings that he needed to start earlier rather than later.