One late winter afternoon, I bundled up my son and carried him outside to the yard. He was a 2½-year-old boy whose speech was delayed for a variety of reasons; he had a couple dozen nouns and a few essential verbs. What did he think? What did he dream about? I didn't know, and as we waited for the lunar eclipse we'd come outside to see, I talked to him about magic and orbits and stars. I explained what I knew about the coming spectacle. When I was done, he suddenly spoke five words in a row, all belonging to him: "Sun breaking moon with shadow." He was telling me, in his own way, what he'd seen in the sky, in a phrase he'd fashioned on his own. It was a moment I'll never forget.

Call it a miracle. Call it instinct. Call it soul. Language is the ship that sails between us. When our children utter words, we hail their extraordinary accomplishment. When they begin to speak in sentences, they introduce us to their minds, and we are humbled by what they have to say.

But where does the gift of speech come from? How is it that the vast majority of children learn to speak without the help of drills, grammar lessons, or speech coaches? Certainly, it isn't a matter of mere imitation: Our children make their own mistakes; create their own sentences and stories; demand the things they want, which are not always what we want for them.

And it isn't easy: Words are but symbols shaped by arbitrary sounds; the rules of grammar are confounding even to adults. Think of all that's difficult about learning a second language. Our toddlers master it with a facility that is astonishing.

---