Babies can say volume without saying a single word. They can wave good-bye, point at things to indicate an interest or shake their heads to mean “No”. These gestures may be very simple, but they are a sign of things to come. Year-old toddlers who use more gestures tend to have more expansive vocabularies several years later. And this link between early gesturing and future linguistic ability may partially explain by children from poorer families tend to have smaller vocabularies than those from richer ones.
Vocabulary size tallies strongly with a child’s academic success, so it’s striking that the lexical gap between rich and poor appears when children are still toddlers and can continue throughout their school life. What is it about a family’s socioeconomic status that so strongly affects their child’s linguistic fate at such an early age?
Obviously, spoken words are a factor. Affluent parents tend to spend more time talking to their kids and use more complicated sentences with a wider range of words. But Meredith Rowe and Susan Goldin-Meadow from the University of Chicago found that actions count too.
Children gesture before they learn to speak and previous studies have shown that even among children with similar spoken skills, those who gesture more frequently during early life tend to know more words later on. Rowe and Goldin-Meadow have shown that differences in gesturing can partly explain the social gradient in vocabulary size.