my son was just using very simple words at that age--no!mum!--maybe 4-5 words like this total. then around 30 months he started saying things like "doggy go", which amazed us because it seemed like he'd never talk. then in the span of 2 months he seriously started overtaking other kids his age in the speech department. now he is the chattiest fellow i know with an amazing vocabluary for his age. give it a little time, keep up the reading to him, talk to him loads and he'll probably be just fine. of course, ask your pediatrician what they think also, can't hurt and may ease your mind.