After having had 2 very verbal kids (now 7 & and 5), I am abit worried about the third, now nearly 20 months. He babbles constantly in a way that sounds like it should be English, but just isn't, understands everything we say including 2 step instructions, and says a handful of words (birdy, dog, bye-bye, bus, waffle (!?)). Usually I don't think twice about it, but every now and then I think he should be putting little sentences together by now and have alot more intelligible words. Should I be worried in any way?