My son is 20 months and barely says anything except a bunch of stuff we don't understand. He talks and talks with passion and conviction all the time....and every once in a while he'll say a word clear as a bell, but then that's it, he doesn't repeat it. I am not worried about it at all. I know in due time he will be talking so much that he will drive us crazy.
He, as well, is learning English and Spanish at the same time and they say when that happens they start talking later. But he understands everything we say, in English and Spanish. So what he doesn't talk yet, he will and yours will, trust me. One other thing, we both have boys, they develop slower than girls. If you are comparing him to a girl his same age, don't. They usually start talking earlier. I have friends with girls who have been talking since before they were 1!! I think all my friends (and family) with boys this age either don't talk or barely do.
Also, don't compare your child to any other. They are all different and develop differently. They say by 4 years they are all basically the same. Don't let anyone tell you something is wrong, everyone seems to have an opinion that they "have" to share with you.
Just love him and let him develop on his own.