When will my son start saying words.?

My sone is 14 months old. He walks, runs, swims (yes swims), can jump, copies alot of things that we do, understands basic orders, waves. He points and says dah!, and he says dada and thats it. no mama, no bye nothing. i know all babies are different, and i dont think something is wrong with him, but other kids in his class, even younger ones SAY bye or bye bye. when did you child start "speaking"?