K.C.
My daughter was a late talker and I went through some of those same questions but when I posed the question to my pediatrican she pointed out that my daughter walked on time if not a little early and mastered all of her motor skills like the pincher grasp, sitting up, crawling etc all on time or early. She pointed this out because she said that many times a child will excel in one area at a time which would explain her late talking. She was great with motor skills but not so much language skills. Is that maybe your son? Is he talking up a storm but just not walking? He could be the opposite, mastering language now and taking a little longer with motor skills. I don't think it's really anything to worry about right now. He sounds like he's right there on the brink and will probably be cruising around in no time.