News in Science

Early talkers benefit from non-verbal clues

Taking cues Giving toddlers non-verbal cues about words can have a big impact on their vocabulary three years later, according to new research.

The work, which was carried out by a research team from the University of Chicago and the University of Pennsylvania, found that differences in what children can see (non-verbal cues) while their parents are talking improved their vocabularies by 22 per cent three years later.

"There are great differences between children in terms of when they start acquiring language and in how fast their vocabularies grow," says Dr Erica Cartmill, the study's lead author. "We know that some of these differences can be attributed to how much speech children hear, but that only explains a portion of the differences."

"We wanted to understand what other differences in children's early home environments might contribute to the differences we see when children are ready to enter school."

To determine how easily a word could be determined from its non-linguistic context alone, the researchers asked 218 adults to guess 50 parents' words from muted videos of their interactions with 14- to 18-month-old children.

This technique, known as the Human Simulation Paradigm (HSP), used the accuracy of the guesses as a measure of how easily a word can be inferred from its context.

They found that some parents' speech to their children contained little contextual information, while others contained much more, and was shared more frequently.

When the researchers followed up with study participants three years later they found that the difference in parent input was significantly correlated with their children's vocabularies prior to starting school.

The findings appear this week in the online edition of Proceedings of the National Academy of Sciences .

Helpful clues

"It is very important to note that these quality differences don't relate to how much parents talk or to the socio-economic status of a family," says Dr Cartmill. "They seem to be independent and an individual matter."

She says that most parents provide contextual information naturally.

"Early in development, children can learn words with only one or two exposures to the word, if these exposures provide a lot of support for the meanings of the words."

"Of course, we're only talking about children learning their very first words. The sorts of cues that help a child learn the word 'ball' won't help them learn 'wish' or 'persnickety' later in life."

Cartmill says that while the study didn't look at children with specific language delay, it does contribute to our understanding of how environmental support aids word learning for children whose language is delayed.

"Language researchers are beginning to have a better understanding of what kinds of features provide support for the meanings of words," she says.

"Talking about objects that are present in the environment seems to be helpful. Looking at objects and sharing attention with your infant also seems to be helpful [as is] gesturing to objects when you label them."

Long-term approach

Dr Penny Levikis, a researcher with the Murdoch Children's Research Institute, says one of the study's most interesting features is its long-term follow-up.

"Normally studies of this kind are followed up in the relatively short term, and often use small, clinical samples, such as children that have been identified with language delays at two years of age," she says.

Levikis adds that while there are many neurobiological and environmental factors that contribute to language development, "this study highlights how important the quality of parental input is to language development."

"It will help us to further understand how language develops in the first five years."

But she adds that while the study shows the association between parent and child intreractions, it doesn't show the cause.

"We don't know whether it is parental input that is driving the child's outcomes, or whether it is the child's language trajectory that drives the parents' response."

"It would be interesting to consider both in future research."