Baby Talk: The Benefits of Bilingualism

Photo: Keith Williamson

To all you new parents out there: if you’re trying to decide whether to spring for that Mandarin-speaking nanny, the answer is yes. Signing up your child for Chinese language kindergarten classes will be far too late.
A study in the Journal of Phonetics about bilingual learning offers new insight into babies and their relationship to the spoken word. Researchers at the University of Washington’s Institute for Learning & Brain Sciences compared the brain functions of babies raised in a monolingual household to those raised in a bilingual household, and found that bilingual babies are more likely to maintain their language learning ability for a longer period of time. From the abstract:

Our results suggest that bilingual infants’ brain responses to speech differ from the pattern shown by monolingual infants. Bilingual infants did not show neural discrimination of either the Spanish or English contrast at 6–9 months. By 10–12 months of age, neural discrimination was observed for both contrasts. Bilingual infants showed continuous improvement in neural discrimination of the phonetic units from both languages with increasing age. Group differences in bilingual infants’ speech discrimination abilities are related to the amount of exposure to each of their native languages in the home. Finally, we show that infants’ later word production measures are significantly related to both their early neural discrimination skills and the amount exposure to the two languages early in development.

The first months of an infant’s intellectual life are largely devoted to narrowing down sounds – what is human speech, and what is ambient noise. For example, at 7 months, a monolingual infant can recognize the difference between the Spanish “da” and the English “ta,” but at 11 months, cannot. The recognition of a subtle sound difference is called a “positive mismatch response.”
By around 10 months, babies are already losing their ability to learn new sounds, and therefore new languages. A baby raised in a bilingual house, however, maintains the ability to distinguish different sounds for longer, until 12 months and possibly longer. The researchers write:

Based on the data available at present from our studies, we put forward the hypothesis that bilingual and monolingual infants show a different timetable for developmental change, with bilingual infants remaining ‘‘open’’ to the effects of language experience longer than monolingual infants, a highly adaptive response to the increased variability of language input that bilingual infants experience.