Learning a second language is certainly useful if you want to travel the world, or if you live in a place where there are a lot of people that speak that language natively. But there are also plenty of benefits beyond simple communication, as a session at this weekend's American Association for the Advancement of Science meeting demonstrated: It gives your brain a much-needed workout and may help to protect against Alzheimer's. Children who become bilingual learn how to prioritize information, as their brains have to figure out how to handle two sets of words for everything. All that mental juggling, as one speaker called it, appears to be a good thing for the brain.
But what intrigued me most was research presented by Janet Werker, a psychologist at the University of British Columbia. She studies babies who grow up in bilingual households and has found that these babies demonstrate certain language abilities at birth that babies exposed to just one language don't. For example, a newborn from a monolingual household will show a preference for listening to its native language only. But a baby born into a bilingual home shows equal interest in both languages it has been exposed to in the womb.
Bilingual infants are also better able to discriminate between languages visually. See, languages look different in the speaker's face. English speakers, for example, produce a "th" sound in which they put their tongue between their teeth, while French speakers do not have this sound in their language and thus don't produce that shape with their tongue. It's how you might be able to pick out a speaker of your native language during a cocktail party in a foreign country when it's too loud to hear distinct sounds.
In Werker's experiments, all babies, monolingual and bilingual, can discriminate between speakers of different language classes at four and six months old, but the monolingual infants lost this ability by eight months of age. The bilingual babies, however, are even more special. In one experiment, Werker exposed eight-month-old babies who grew up in households speaking Spanish, Catalan, or Spanish and Catalan (i.e., bilingual) to videos of women speaking English or French. The bilingual babies, but not the monolingual ones, were able to tell the difference between the two unfamiliar languages.
"The number one lesson is that learning two languages is as natural as learning just one," Werker says. Babies learn through listening and watching to figure out the properties of language, whether it's one or two, and bilingual babies are able to figure out which is which and not confuse the two.