From the University of Utah medical school:
By 12-15 months, kids should have a wide range of speech sounds in their babbling, like the p, b, m, d, or n sounds. They should begin to imitate sounds and words modeled by family members, and typically say one or more words other than just "Momma" and "Dadda." Nouns usually come first, like "baby" and "ball." Other things would be things like "uh-oh" or "wow" or "no," which is a very popular first word.
From 18-24 months, there's a lot of variability. This is when we talk about the language explosion. Most toddlers are saying about 20 words by 18 months and 50 or more words by the time they turn two. By age two, kids are starting to combine words together to make two word sentences such as "baby crying" or "come help." A two year old should be able to identify common objects as well. If you point to a picture in a book of an object that they know, like a baby, they should be able to tell you that. They should also be able to point to their facial features when asked, and follow two step commands like "please pick up the toy and give it to me."
I think it's way too early for anyone, especially us folks that see 20 minutes of the kid a day (or less if you're like me and stopped watching the USB and Commode channel), to diagnose him with anything.