J.V.
I think that it sounds like a good time to get him some early intervention speech assistance. Usually your local regional service or "search and serve" school in your district can direct you. It will just help him at a young age to develop some of the speech that is challenging him. It doesn't mean that he is delayed in intellect, he just might need some help with the speech. It can't hurt to investigate your options. Plus, he might have fun learning some of the sounds.
My daughter's son is younger and he wasn't speaking at all, but cognitively understanding everything. She taught him some basic sign so that he could communicate what he couldn't get out verbally. It reduced his frustration.
Best wishes.
J. K-V
www.AisForAutism.net