Nov. 4, 2002 -- It's never too soon -- or too late for a child to learn a second language. Children who learn to speak two languages at once sound like a native in both tongues. What's more, they learn to talk at the same speed as kids who learn only a single language.
The findings come from a study led by Laura-Ann Petitto, PhD, director of the cognitive neuroscience laboratory for language and child development at Dartmouth College, Hanover, N.H. At this week's meeting of the Society for Neuroscience, Petitto reported a study of 15 children who learned a second language at various ages.
The children learned French and English; Spanish and French; or Russian and French. They also included children in French-speaking communities whose deaf parents taught them sign language. Children began learning the second language at birth, at age 2-3 years, at age 4-6 years, or at age 7-9 years.
"The earlier a child was exposed to a second language, the better the child did," Petitto tells WebMD. "This flies in the face of educational policy that says expose a child to only to one language at first. This does not support the holding policy that today is rampant in education. A child is not confused by a second language or delayed in learning the community language."
No matter what age these kids began to learn a second tongue, they learned it better if they picked it up in their families or communities than if they learned it in a classroom setting. And while bilingual children didn't learn to speak any sooner or later than single-language kids, they did get one extra advantage besides their added fluency.
"Interestingly, bilingual children are better than [single-language] children in aspects of [thinking] that require them to switch attention," Petitto says. "Because they are switching attention between two languages, a byproduct is enhancement in activities that use this skill."
Petitto tested the children on several aspects of language -- including the types of words and grammar they learned, the sounds they made, and whether, to a native speaker, they had native- or foreign-sounding accents. While children who first learned one language and then learned another quickly became fluent in their second tongue, they were never quite as excellent as those who learned two languages at once.
"We tested children on the whole landscape of human language -- and the earlier they were exposed to a second language, the more masterful they were in each of these areas," Petitto says. "So later-exposed children can say lots of words in French and Russian, but their second language had a heavy accent and they didn't have as good grammar. They would immediately be identified as a foreign speaker."
Bilingual learning expert Ellen Bialystok, PhD, is professor of psychology at York University, Toronto. She warns that Petitto's study does not show that a second language can be learned only during a critical period of childhood.
"It is not a bad thing to start late," Bialystok tells WebMD. "It is never too late to learn a second language. I don't want people to get the idea [from Petitto's study] that there is no point in beginning later or that some cost or compromise is made."
Petitto says that the brain changes during the teen years, making it impossible for an adult to learn a language the same way that a child does. Bialystok agrees that it's a totally different thing for an adult to learn a language -- but stresses that it's still a good thing to do.
"Probably someone who begins to learn a second language at age 20 would not sound like a native even at age 40," Bialystok says. "The reason is not that their brains have passed some critical time when it is only possible to do this. There is simply no sense in which the actual mechanics of how language is learned is same at 20 as it is at age 5. You learn in different contexts, you talk about different things, you already fully have your first language, your life is busier -- so it's just not the same thing."
Petitto is now studying the changes that happen to the brain when a second language is learned.