It turns out, you need words to have an imagination. Since Tucker's words were late to arrive, his imagination also waited a bit to appear.
But it's here.
Today, he stopped mid-stride, put his hand to his ear, and said, "Hey! Do you hear that sound?"
I listened. "No, I don't hear anything."
"Listen. Hear it? It's a cow. And it's coming. In the house, very fast. Run!"
And he took off. And I finished folding laundry, not terribly concerned about being consumed by cattle. But Tyler ran alongside him, since a little brother can never be too sure.