I would say you're about where we were. We started about then, and he uses a handful of signs still (at 21 months). He even came up with a few of his own! But it's nice, because he can ask for things he still can't pronounce (though he still signs for things he can sometimes), such as "medicine", which he understands the use of. He has signs for medicine, eat/food, thirsty, all done, please, more, help, rooster (that one was his), thank you.... (that's what I can think of). They really do help, and have since before he was really speaking. He can say "all done," "please" and "thank you" now, but chooses to use the signs for those. But he does have probably 100 words now, if not more, and he's far less frustrated when we understand what he's asking for than he would be if he couldn't pronounce those things.
Give it time, and be patient and consistent. They'll get it with time! =)
at 2:45 AM on May. 16, 2010