My son was a late talker too. We did some tests(like hearing) and they came out fine. We were not too worried about it, but the doctor was pushy. We started working with some sign language for him, which he loved, and talked to him constantly. At about 27 months, he started talking in full sentences and now he never stops! He just seemed to be taking it all in first before he was ready to talk. You should feel OK to give him more time unless he's showing any hearing problems.
There was one other issue with our son that may have delayed his talking -- he had a problem with his tongue. The piece under the tounge came all the way to the tip of his tongue so he could not move his tongue very much. We don't know if this contributed to his delayed speech (although it turned out to be why he was so poor at breastfeeding). He got that piece cut at 25 months and may need speech therapy later because the sounds he did learn before that he learned wrong. But he's great now and talks nonstop at 2 and a half. You may want to check for something like that.
But I think it's fine to give it time. If you're comparing with friends with girls, girls talk a lot sooner. Good luck.