Some kids are better than others at understanding complex language. Scientists thought this was an in-born ability.

But as this ScienCentral News video reports, new research shows that the way we speak to children has a huge effect.

Input affects output

Preschoolers can’t typically read or write, and their conversation is anything but adult. So it’s easy to think that speaking to them in very simple language would be a good thing. But learning researchers have found that the amount of complex speech kids hear has a large effect on their ability to learn to process such speech. The upshot is that what goes in helps determine what comes out.

Janellen Huttenlocher, professor of psychology at the University of Chicago, tested the language comprehension of more than 300 preschoolers (3- and 4-year-olds) at the beginning and end of the school year. Kids were presented with three drawings and had to decide which one matched a complex sentence that was read to them. (For example, “The girl played with her blocks because she couldn’t reach her other toys.”) In the middle of the school year, the teachers were observed to determine what percentage of their speech was complex—that is, how often they used multiclause sentences like the one above. The amount of complex speech used by teachers varied from 11 to 32 percent.

In classrooms where teachers used the most complex speech, students’ language comprehension grew at twice the rate of children whose teachers did not use as much complex speech.

“We were astounded,” says Huttenlocher. “The data were so striking and so unambiguous that it was really one of the more thrilling moments that I’ve had [as a researcher].”

Huttenlocher had already shown that the amount of complex speech used by children’s parents affected the kids’ language comprehension. But that study left a lot of room for genetics to play a role. By showing a strong connection between teacher s’ speech and improvement in language comprehension, it calls into question assumptions that syntactical ability like this is a predetermined, in-born trait. And it also suggests the extent to which we can help kids that start out at a disadvantage to begin with.

In fact, one of the study’s most encouraging findings came from the fact that the researchers were careful to cover the full range of socioeconomic backgrounds: high-income, low-income, and mixed.

“Kids from families that were uneducated and poor were less likely to have complex speech at the start of the school year,” says Huttenlocher. “However the amount of growth in comprehension was related strongly to the teachers’ speech.”

On the other hand, if a child started the school year with a high level of comprehension, being in a classroom with very little complex speech resulted in either no improvement or, in some cases, a worsening in comprehension. The socioeconomic background of the students was not related to the amount of complex speech used by their teachers.

“The lesson is that it isn’t to be neglected, the question of the kind of speech your child is hearing,” says Huttenlocher.

What does this mean for parents and teachers?

Huttenlocher dispels the idea that parents and teachers will be able to suddenly change the way they speak to kids. And besides, she says, “You’re not going to want to be focusing on the sentences. You’re going to want to focus on the kind of explanations you’re giving kids. And explanations that have some degree of complexity will naturally be described in more complex speech.”

This is not to say that a physics lesson is in order when your child wants a push on the swing set.

“I think the most important thing is to be thinking about what the child sort of knows but doesn’t quite understand,” says Huttenlocher. “And to try to talk sort of at the cutting edge of the child’s ability to understand events.”

Meanwhile, Huttenlocher says that parents might want to pay close attention to the way teachers in a preschool speak to the students, and whether the teachers read to the kids a lot. And she says that, at home, parents “might want to read interesting stories to their kids. Not just stories that exhibit simple ongoing activities, but those that explore inner states of people and causal relations and so on.”

Her work, which was published in the October issue of the journal Cognitive Psychology, was funded in part by a grant from the McCormick Tribune Foundation.