At four months old, babies can tell when a speaker changes languages using only expressions on the speaker's face.
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WASHINGTON: At just four months, babies can tell the difference between two languages spoken to them using only the expressions on a speaker's face, according to a new Canadian study.
However, this ability disappears by the time they are eight months old, unless they grow up in a bilingual home.
Testing infants from four to eight months old on silent video clips of people alternatively speaking French and English - the two main languages in Canada - researcher Whitney Weikum from the University of British Columbia (UBC) discovered that even the youngest paid closer attention and watched longer if a speaker changed languages.
Facial cues
Six-month-old babies, even those from monolingual homes, could discern the different languages visually, according to a summary of the research, published this week in the U.S. journal Science
But by eight months, babies from single-language homes could no longer tell the difference by viewing the speaker's face alone, though those from bilingual homes could still tell from facial cues.
In the study, infants watched three silent clips of bilingual French-English speakers, who delivered sentences in one language before switching to the other. The infants would quickly grow bored with the video, but their interest was renewed when the speaker changed to another language – evident through visual information alone.
"We already know that babies can tell languages apart using auditory cues," said Weikum, a UBC neuroscience doctoral student who worked on the study with psychology professor Janet Werker. "But this is the first study to show that young babies are prepared to tell languages apart using only visual information."
Bilingual advantage
The results of the study - which tested five groups of infants from monolingual English and bilingual English-French homes - demonstrated that babies growing up in a bilingual environment "advantageously maintain the discrimination abilities needed for separating and learning multiple languages," the summary said.
It is one of many "amazing capabilities" that Weikum has seen in young infants, which continue to astound researchers. Recent studies have found that infants exposed to sign language at an early age can "babble" with their hands, and newborn babies are able to recognise their mother tongue.
But Weikum said the results on the oldest infants show that by eight months, only babies learning more than one language need to maintain this visual skill. "Babies who only hear and see one language don't need this ability, and their sensitivity to visual language information from other languages declines."
