WASHINGTON, D.C.—Your baby's language skills may surprise you. Before they speak—before they even crawl—infants can distinguish between two languages they've never heard before just by looking at the face of a speaker. And if they're raised in a bilingual household, they retain this ability for a long time, according to research presented here today at the annual meeting of the American Association for the Advancement of Science  (which publishes ScienceNOW).
It might seem like all babies think about at 8 months is food and diapers. But it's actually possible to measure their interest in other topics. Developmental psychologist Janet Werker of the University of British Columbia in Canada shows babies videos and uses "looking time"—the amount of time they spend looking at the video—as a measure of what they're interested in.
In a recent experiment, Werker and a colleague from Barcelona measured looking time in 8-month-old Spanish babies. Some were born in homes in which only Spanish is spoken, some in homes whose residents only spoke Catalan (a Romance language spoken in northeastern Spain), and some in bilingual homes.
The babies were shown a video of three women who were bilingual speakers of French and English—languages the babies didn't know. Each woman was shown in turn saying sentences in one of the languages. Eventually, the baby got used to this and got bored. Then the language changed. Monolingual babies took no notice, but bilingual babies started looking at the video again. Other studies have shown that monolingual babies make the distinction until they are 6 months old.
The findings indicate that as babies learn to discriminate the two languages they're familiar with—Spanish and Catalan—they aren't just learning the specific rules of their two mother tongues. They're actually learning something more general about what makes languages different. Monolingual babies lose this skill over time.
The new work fits in with other research on bilingualism, including some discussed at the same press conference by psychologist Ellen Bialystok of York University in Toronto, Canada, showing that people who speak two languages are stronger at important cognitive abilities like complex thought and controlling attention. Bilingualism even seems to delay the onset of dementia in old age.
Werker doesn't know yet exactly what the babies are seeing in the faces of the speakers. But English and French do look different when spoken. "French, for example, has many more rounded vowels. As one of my friends says, it looks like French people are always kissing you," Werker says. "They may also be paying attention to the simple rhythm of your jaw opening and closing, the whole ensemble of muscle movements in the face."