Your baby’s vocabulary is more than just the words they can say.

Everyone has both a receptive vocabulary and a productive vocabulary. Combined, they hold all the words we know.

A vocabulary is well known to be all the words a person knows. A receptive vocabulary describes all the words a person understands, and is also called a comprehension vocabulary. A productive vocabulary describes all the words a person can say or sign, and is also called an expressive vocabulary.

A baby with a thought bubble that contains a dictionary.
Babies know more words than they say.

For babies and adults learning a language, it’s not uncommon for them to be able to understand more words than they can say. This is especially true for babies learning language. In this case, their receptive vocabularies are bigger than their productive vocabularies. As an infant learns how to say or sign words, their productive vocabulary grows.

Aahnix poses for a picture on a chair, facing the sunset.

Aahnix Bathurst


Aahnix is a Project Coordinator in the Bergelson lab at Duke University

Elika Bergelson

Principal Investigator