Babies grasp word meanings even before they can talk: study

Babies develop a far better understanding of language even before they can speak to us in words, according to a study.

"Even though there are not many overt signals of language knowledge in babies, language is definitely developing furiously under the surface," said Elika Bergelson, assistant professor at Duke University in the US.

The study, published in the journal PNAS, used eye- tracking software to show that babies also recognise that the meanings of some words, such as car and stroller, are more alike than others, like car and juice.

By analysing home recordings, the team found that babies' word knowledge correlated with the proportion of time they heard people talking about objects in their immediate surroundings.

"Even in the very early stages of comprehension, babies seem to know something about how words relate to each other," Bergelson said.

"And already by six months, measurable aspects of their home environment predict how much of this early level of knowledge they have.

"There are clear follow-ups for potential intervention work with children who might be at-risk for language delays or deficits," said Bergelson.

To gauge word comprehension, Bergelson invited babies and their caregivers into a lab equipped with a computer screen and few other infant distractions.

The babies were shown pairs of images that were related, like a foot and a hand, or unrelated, like a foot and a carton of milk.

For each pair, the caregiver (who could not see the screen) was prompted to name one of the images while an eye- tracking device followed the baby's gaze.

Bergelson found that babies spent more time looking at the image that was named when the two images were unrelated than when they were related.

"They may not know the full-fledged adult meaning of a word, but they seem to recognise that there is something more similar to the meaning of these words than those words," Bergelson said.

Bergelson then wanted to investigate how babies' performance in the lab might be linked to the speech they hear at home.

"It turned out that the proportion of the time that parents talked about something when it was actually there to be seen and learned from correlated with the babies' overall comprehension," Bergelson said.