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What the bilingual brain tells us about language learning

By Arturo E. Hernandez


One of the most common questions people ask revolves around when and how to learn a second language. One common view is that earlier is better. There is good evidence for this view. A number of studies have found that the earlier a person learns a second language, the better they perform on a number of tests. Particularly sensitive to age is a person’s ability to speak without an accent and to detect speech sounds that are not present in their native language. For example, infants can detect sounds from a language not in their environment at six months of age. By 10 months of age they lose this ability. This suggests that the ability to detect speech sounds from around the globe is available to all infants but slowly fades away. Another arena where age plays a role is in the processing of grammar. Those who learn a second language later in life do not perform as well on tests of grammar as early learners. Hence, the ability to learn grammar and speech sounds appears to be very dependent on the age that one first learns a language.

Rodin's Thinker full bodyDespite this general rule, there are some very interesting exceptions. For example, Christophe Pallier and his colleagues tested a group of adults who had been born in Korea and adopted as children in France between the ages of 4-8. This group of adults were asked to listen to sentences in Korean, French, or an unknown language. The results revealed no difference in their brain activity when compared to native French speakers. That is, both groups showed similar activity for French, Korean, and a foreign language. Furthermore, the Korean adoptees had no discernible accent. They sounded French. The results are intriguing because they suggest that a language can be lost even relatively late in childhood. This suggests that the age at which a language is learned is not the only predictor of how well a language is spoken as an adult.

This complex form of language representation is also found when observing the effects of brain damage on bilingual individuals. For over 100 years, neurologists and neuropsychologists had observed a lot of differences in the pattern of language loss in bilinguals. There were cases of people who lost access to one or both languages after suffering brain damage. Some lost access to the first language and others lost access to the second language. I also experienced a brief period of language inaccessibility when immersed in Portuguese, my third language. When I returned from my time abroad, I began to read about cases of bilingual aphasia. The resonance between language loss due to stroke and what I had experienced was interesting. I wondered why there was such a dynamic aspect to language access in bilinguals — questions that I began to ask myself 24 years ago.

Arturo Hernandez is currently Professor of Psychology and Director of the Developmental Cognitive Neuroscience graduate program at the University of Houston. He is the author of The Bilingual Brain. His major research interest is in the neural underpinnings of bilingual language processing and second language acquisition in children and adults. He has used a variety of neuroimaging methods as well as behavioral techniques to investigate these phenomena which have been published in a number of peer reviewed journal articles. His research is currently funded by a grant from the National Institutes of Child Health and Human Development.

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Image credit: Thinker, created by Auguste Rodin at the end of the 18 century. San Francisco Legion of Honor. © rramirez125 via iStockphoto.

Recent Comments

  1. Andrew Weiler

    The suggestions that learning languages early are easier at an early age has been put by many people for different reasons. I think the motivation for that comes from the fact that so many adults have so many difficulties in learning languages later on. So these reasons come forth.
    Of course there are a differences in the capacities of babes and adults HOWEVER we should not forget that there are many polyglots who completely master many languages. These “exceptions” are discounted because they have “talent” or some such thing.
    The reality is that we ALL mastered our first language so we have demonstrated we have the talent. It is just that we get distracted from these talents for a number of reasons, a key one being the ineffective ways we are taught. The reality is that we all can rediscover our capacities under the right conditions. If you are interested in what they may be do read the recently published book, Language Learning Unlocked by Andrew Weiler

  2. AMB

    It is folklore to claim that children learn all aspects of language better. (Phonology being the exception). Usually, if a kid learns a foreign language, it is because (s)he is immersed in it. So (s)he has this huge amount of time on task. And, of course, if you are talking about toddlers learning their first language, well, then the comparison is just ridiculous because they not only spend all their waking time immersed in the language, but have a very REAL and urgent motivation to learn it. Compare that to how an adult usually learns a language – you will almost always see less time on task, less time getting input and trying to use the language. Looking at the age at which a language was learned and grammatical competency does not account for how much TIME WAS SPENT learning that language, and this is key.

  3. Sue Sully

    Despite the influence of environment and attitudes, learning languages is the work of cerebral processes. The subconscious networks that process our first language and establish the automaticity in speaking and hearing we expect in our first language, are less available as time goes on. Hence teenagers might do a good job of mastering a second language while a 40 year old less so. These are not myths. The conscious networks adults access to learn a second language are far less able to process the complexities of language than the implicit linguistic procedures activated and available during childhood. As neural imaging can now establish, time, immersion and motivation are only bit players in the dramatic spectacle that is language acquisition. The loss of plasticity in those neural networks dealing with processing a new language underlies the struggle for adults in this area. Sue Sullivan

  4. Karen

    I ran my own experiment on the age/language acquisition hypothesis. I was 35 when I moved to France as a trailing spouse who had never studied French. My daughter was 4 and also only spoke English. Thus we learned French immersion-style at the same time, but it was clear that it was not at all in the same way. I constantly had to think through and translate in my head. She never seemed to do this at all. At 4 kids are still acquiring a lot of vocabulary, and in her case there were some words she only knew in English and others she only knew in French. Whether speaking English or French, she would select the word she knew without missing a beat. It drove her father crazy that she would mix the languages in that way. But by age 6, the languages separated and she no longer borrowed words from the other language. Within 3 months of our arrival in France, she was speaking French, and by 6 months you could not tell her apart from the French kids in her maternelle. With her Parisian accent, no one would ever guess that she had American parents (both with strong accents when speaking French). At age 4, she would correct my grammar if, for example, I mis-conjugated a verb. She didn’t read at that point and had no notion of grammar rules, but she knew when I had made a mistake and could correct it accurately.

    In her 5th grade year (CM2 in the French system), they exposed the kids to a foreign language (in her case it was English). So her father and I decided that she should study another language outside of school. She chose Arabic, and for a year she took classes at the Institut du Monde Arabe. These classes were designed for kids with at least one Arabic-speaking parent so that they could become literate. This was obviously not her situation (and we couldn’t help her with her Arabic lessons), but she excelled and really loved it.

    When she was 10, we moved to German-speaking Switzerland, and she learned German very easily. Switzerland is a tough place to learn high German because of the dialects. I found it to be impossible and finally just learned enough of the local dialect to get through the daily transactions and left it at that. German and English were the foreign languages taught at her French school, and she picked up German easily. She wouldn’t speak dialect (only high German), but she could understand it, which was important for her extracurricular activities (dance and orchestra). I think her refusal to speak dialect may have been due to inhibition — not wanting to “parrot” the other kids — something that didn’t faze her when she was 4 and learning French. But it may also have been because of the contrast between the high German she was taught and the seemingly much less rule-bound dialect.

    She decided to go to university in the US and resumed studying Arabic, which still came very easy to her. I visited her when she was studying Arabic dialect in Beirut one summer and was impressed by how fluidly she could speak and even stubbornly negotiate taxi rates. So maybe the inhibition theory I posited above is not accurate.

    In any case, it seems to me that the fact my daughter became bilingual at a young age affected the way in which she learned French as well as the other languages she later acquired. Anecdotal, I acknowledge. But if the mere passage of time were the key, my French would be better than hers as I have now lived in France longer than she did. And that’s absolutely not the case. I live and work in France in a research position and my comprehension, both oral and written, is excellent. But my strong accent remains. I still make the same annoying mistakes and in fact sometimes feel like my spoken French is getting worse. But when my daughter comes home to Paris on school breaks, she slips right back into perfect French with her friends. Not fair, mais c’est la vie!

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