most children do not say as many words as your son. my daughter was the same way, it means he is advanced in language and sound. be sure to see if others can understand the words also, sometimes we understand them because we know them so well and see their actions at the same time.
for a boy it is even more unusual, it is good to read to him and show him letters and makes the phonic sounds. there are great edu toys out there that help. as he gets older try to keep a love of language in him, sometimes children who are "quicker" get board in school and feel unchallenged, which leads them into trouble.
Also remember his age, just because he can speak well doesn't mean that he has passed through some stages of growth and many times people will judge him on his language and expect more of him thinking he is older.
i also agree with kelly f. well done mom.