Beeb beeb. That is the car. It is also the pram, the toy car, the cardboard box he sits in and steers like a bobsleigh, and my father’s wheelchair.

Anything that moves is beeb beeb. Anything that has ever moved is beeb beeb. A parked car is beeb beeb because it is only resting.

The wheelchair is the one that stops the room. He says it with the same delight he gives the toy car. Because to him it is the same thing. This thing goes. My father laughs every time. He has been called worse.

There is a word for what my son is doing. Linguists call it overextension. A child takes one word and stretches it to cover more of the world than the word was built for. Doggy for every animal with four legs. Daddy for every adult man, which is a moment for the family and a difficult afternoon for the guest. Ball for the balloon, the apple, the egg, the moon.

It has an opposite. Underextension. The word comes out too small. Car means our car and no other car. Kitty is the cat on our street. The ones two streets over do not count. Shoe is his shoe. Not mine.

My son does not underextend. Not once. He runs this household on few words and beeb beeb does more work than the other together.

Maybe he is lazy. I have thought about it seriously. He worked out that two syllables repeated will cover enough of the world to get by. Why learn wheelchair. Why learn pram, trolley, bicycle, bus, when beeb beeb arrives faster and has never once been misunderstood.

And I envy him. I have spent forty minutes choosing between two words that meant the same thing to everyone but me. He points. He says beeb beeb. Everything arrives.

But this is the part I actually sat down to write.

Parents hear this and something tightens. Their child calls the wheelchair a car, calls the neighbour daddy, calls the moon a ball, and they start counting months. They wonder if the words are late. If something is wrong. I have watched that face at family gatherings. I have made that face.

He is not confused. He is sorting. A child who calls the wheelchair beeb beeb has not mistaken it for a car. He has built a category in his head called things that go. Nobody has given him enough words yet to break that category into smaller pieces. He is not making mistakes. He is drawing a map. And we are watching him draw it.

And he understands more than he says. Ask him for the ball while he is holding the apple and watch which one he hands over. He knows the difference. His mouth just has not caught up with his brain. That gap is normal. Adults have the same gap. We just stop talking about it.

My mother watches all of this and says there must be something wrong. She has raised more children than any paper I could read. Yet I’m the expert in this situation both as his dad and from academic perspective.

So it is Normal. Loudly normal. It happens in every language anyone has studied. And it happens in the same categories every time. Animals. Vehicles. Food. Shapes. Different homes. Different children. Same work.

He will lose it. That is the part nobody warns you about. Someone will teach him wheelchair. And pram. And bus. And each new word will take a piece of beeb beeb away. The world will get more accurate and much smaller. He will be precise. And precision costs something.

I have thousands of words. I use them all day. At work. On this blog. In two languages. And I still cannot get one of them to hold everything I mean.

He has one word that holds everything that moves.

I know which of us has the bigger vocabulary.