Blog: Latino Ed Beat

New Study: Bilingual Babies’ Speech Perceptions Stay Flexible Longer

New research from the University of Washington’s Institute for Learning and Brain Sciences shows that bilingual babies stay open to different speech sounds for a longer period than monolingual babies and that the relative amount of each language babies are exposed to affects their vocabulary as toddlers. Not surprisingly, in a sample of English/Spanish bilingual babies, the more of one language they heard, the more of that language they spoke at 15 months.

In previous studies, the researchers have found that between eight and 10 months of age, monolingual babies become more able to distinguish the speech sounds of their native language. At the same time, their ability to distinguish foreign speech sounds declines. For instance, English-speaking babies become better able to distinguish “r” from “l” sounds at this age, while Japanese-speaking peers (who don’t hear those sounds as often) lose the ability to differentiate them.






The researchers followed up when the babies were about 15 months old to see how many Spanish and English words the children knew. They found that early brain responses to language could predict infants’ word-learning ability. That is, the size of the bilingual children’s vocabulary was associated with the strength of their brain responses in discriminating languages at 10-12 months of age.

Early exposure to language also made a difference: Bilingual babies exposed to more English at home, including from their parents, other relatives and family friends, subsequently produced more words in English. The pattern held true for Spanish. (On a personal note, I’ve observed the same effect on my own son. At 15 months or so I think he was probably speaking more Spanish–he heard a lot of Spanish his first year of life–but now at age two he speaks more English, as his exposure to English has increased.)


“Learning a second language is like learning a sport,” said Garcia-Sierra, who is raising his two young children as bilingual. “The more you play, the better you get.”



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