Learning a new language
Musicians and people who are bilingual have long been shown to have a better working memory, and a new study makes a start on identifying why this might be so.
The brain imaging study, involving 41 young adults (aged 19-35), who were either monolingual non-musicians, monolingual musicians, or bilingual non-musicians, found that musicians and bilinguals needed fewer brain resources when remembering sounds.
Participants were asked to identify whether the sound they heard was the same type as the previous one, and if the sound came from the same direction as the previous one. Sounds from musical instruments, the environment and humans were among those used in the study.
Musicians remembered the type of sound faster than individuals in the other groups, and bilinguals and musicians performed better than monolinguals on the location task. Although bilinguals remembered the sound at about the same level as monolingual non-musicians, their brains showed less activity when completing the task.
In both tasks and both levels of difficulty, musicians showed lower brain activity in the superior prefrontal frontal gyrus and dorsolateral prefrontal cortex bilaterally, which is thought to reflect better use of neural resources. Bilinguals showed increased activity in language-related areas (left DLPFC and left supramarginal gyrus), which may reflect a need to suppress interference associated with competing semantic activations from multiple languages.
The findings demonstrate that musical training and bilingualism benefit executive functioning and working memory via different activities and networks.
 Alain C, Khatamian Y, He Y, Lee Y, Moreno S, Leung AWS, Bialystok E. Different neural activities support auditory working memory in musicians and bilinguals. Annals of the New York Academy of Sciences [Internet]. Submitted . Available from: https://nyaspubs.onlinelibrary.wiley.com/doi/abs/10.1111/nyas.13717
A small study using an artificial language adds to evidence that new vocabulary is learned more easily when the learner uses gestures.
“Vimmish”, the artificial language used in the study, follows similar phonetic rules to Italian. The German-speaking participants were given abstract and concrete nouns to learn over the course of a week. In the first experiment, the 21 subjects heard the words and their translations under one of three conditions:
On the 8th day, the participants were tested while their brain activity was monitored. The test involved hearing the foreign word, then selecting the correct translation from four written options.
The researchers were interested in learning whether they could predict the learning condition from the brain activity patterns displayed when the participants were tested. They found that the gesture condition and control could be distinguished in two brain regions: a visual area that processes biological motion (part of the right superior temporal sulcus), and the left premotor cortex. Activity in these regions was also significantly correlated with performance. The picture condition and control could be distinguished in a visual area that processes objects (the right anterior lateral occipital cortex). There was a trend for this activity to correlate with performance, but it didn't reach significance.
Paper-and-pencil translation tests two and six months after learning showed that learning with gestures was significantly better than the other conditions. But note that there was no advantage for any condition in a free recall task.
A second experiment compared gesture and pictures in the more common picture scenario — participants only viewed the video or picture; there was no imitation. Unsurprisingly, there was no motor cortex involvement in this scenario: gesture and control conditions were distinguished only by activity in the biological motion part of the right superior temporal sulcus. The correlation of activity in the right anterior LOC with performance in the picture condition this time reached significance. But most importantly, this time the picture condition led to better translation accuracy than the other two conditions.
However, the most significant result is this: when both experiments were evaluated together, the gesture benefit in experiment 1 (when the participant copied the gesture) was greater than the picture benefit in the second experiment.
The findings are in keeping with other evidence that foreign words are learned more easily when multiple senses are involved.
 Mayer KM, Yildiz IB, Macedonia M, von Kriegstein K. Visual and Motor Cortices Differentially Support the Translation of Foreign Language Words. Current Biology [Internet]. 2015 ;25(4):530 - 535. Available from: http://www.sciencedirect.com/science/article/pii/S0960982214015693
A small study that compared teaching Spanish-speaking children English vocabulary using a song or a spoken poem has found definite and long-term advantages to the song form.
The study involved 38 Spanish-speaking Ecuadorian children (aged 9-13), of whom 22 were randomly assigned to learn a 29-word English text as an oral poem, and 16 learned it as a song. None of the children had had any formal instruction in English; all had some limited music training. The children were given 4 training sessions and 3 testing sessions over two weeks, with a final test for 13 children six months later.
Children in the song condition out-performed those in the spoken condition on every measure: their ability to recall the passage verbatim, pronounce the words, and translate target terms from English to Spanish.
While pronunciation of vowels was notably better, though there was no difference in consonants.
Long-term recall is of course the main question of interest: six months after this little experiment, with no English instruction since, those from the song condition could recall without prompting an average of 8.83 words out of 10 target words, compared with 0.29 words for those from the spoken condition. However, there was no significant difference in translation success, which was extremely low in both cases (2.26 vs 1.07 — this compares with 4.03 vs 2.69 at the end of training).
The song itself, its melody and rhythmic structure, was remembered very well. The children in the song condition also enjoyed the learning sessions much more.
The study is small, and comes with several caveats, but it does provide support for the use of songs as an adjunct to foreign language learning.
 Good AJ, Russo FA, Sullivan J. The efficacy of singing in foreign-language learning. Psychology of Music [Internet]. 2015 ;43(5):627 - 640. Available from: http://pom.sagepub.com/content/43/5/627
Foreign language learning increases the white matter in the language network and the bridge joining the hemispheres, perhaps helping explain why bilinguals have better executive control.
In my last report, I discussed a finding that intensive foreign language learning ‘grew’ the size of certain brain regions. This growth reflects gray matter increase. Another recent study looks at a different aspect: white matter.
In the study, monthly brain scans were taken of 27 college students, of whom 11 were taking an intensive nine-month Chinese language course. These brain scans were specifically aimed at tracking white matter changes in the students’ brains.
Significant changes were indeed observed in the brains of the language learners. To the researchers’ surprise, however, the biggest changes were observed in an area not previously considered part of the language network: the white matter tracts that cross the corpus callosum, the main bridge between the hemispheres. (I’m not quite sure why they were surprised, since a previous study had found that bilinguals showed higher white matter integrity in the corpus callosum.)
Significant changes were also observed within the left-hemisphere language network and in the right temporal lobe. The rate of increase in white matter was linear, showing a steady progression with each passing month.
The researchers suggest that plasticity in the adult brain may differ from that seen in children’s brains. While children’s brains change mainly through the pruning of unwanted connections and the death of unwanted cells, adult brains may rely mainly on neurogenesis and myelinogenesis.
The growth of new myelin is a process that is still largely mysterious, but it’s suggested that activity at the axons (the extensions of neurons that carry the electrical signals) might trigger increases in the size, density, or number of oligodendrocytes (the cells responsible for the myelin sheaths). This process is thought to be mediated by astrocytes, and in recent years we have begun to realize that astrocytes, long regarded as mere ‘support cells’, are in fact quite important for learning and memory. Just how important is something researchers are still working on.
The finding of changes between the frontal hemispheres and caudate nuclei is consistent with a previously-expressed idea that language learning requires the development of a network to control switching between languages.
Does the development of such a network enhance the task-switching facility in working memory? Previous research has found that bilinguals tend to have better executive control than monolinguals, and it has been suggested that the experience of managing two (or more) languages reorganizes certain brain networks, creating a more effective basis for executive control.
As in the previous study, the language studied was very different from the students’ native language, and they had no previous experience of it. The level of intensity was of course much less.
I do wonder if the fact that the language being studied was Mandarin Chinese limits the generality of these findings. Because of the pictorial nature of the written language, Chinese has been shown to involve a wider network of regions than European languages.
Nevertheless, the findings add to the evidence that adult brains retain the capacity to reorganize themselves, and add to growing evidence that we should be paying more attention to white matter changes.
 Schlegel AA, Rudelson JJ, Tse PU. White Matter Structure Changes as Adults Learn a Second Language. Journal of Cognitive Neuroscience [Internet]. 2012 ;24(8):1664 - 1670. Available from: http://dx.doi.org/10.1162/jocn_a_00240
Bialystok, E., Craik, F. I. M., & Luk, G. (2012). Bilingualism: consequences for mind and brain. Trends in Cognitive Sciences, 16(4), 240–250. doi:10.1016/j.tics.2012.03.001
Luk, G. et al. (2011) Lifelong bilingualism maintains white matter integrity in older adults. J. Neurosci. 31, 16808–16813
A new study adds to the growing evidence for the cognitive benefits of learning a new language, and hints at why some people might be better at this than others.
A small Swedish brain imaging study adds to the evidence for the cognitive benefits of learning a new language by investigating the brain changes in students undergoing a highly intensive language course.
The study involved an unusual group: conscripts in the Swedish Armed Forces Interpreter Academy. These young people, selected for their talent for languages, undergo an intensive course to allow them to learn a completely novel language (Egyptian Arabic, Russian or Dari) fluently within ten months. This requires them to acquire new vocabulary at a rate of 300-500 words every week.
Brain scans were taken of 14 right-handed volunteers from this group (6 women; 8 men), and 17 controls that were matched for age, years of education, intelligence, and emotional stability. The controls were medical and cognitive science students. The scans were taken before the start of the course/semester, and three months later.
The brain scans revealed that the language students showed significantly greater changes in several specific regions. These regions included three areas in the left hemisphere: the dorsal middle frontal gyrus, the inferior frontal gyrus, and the superior temporal gyrus. These regions all grew significantly. There was also some, more selective and smaller, growth in the middle frontal gyrus and inferior frontal gyrus in the right hemisphere. The hippocampus also grew significantly more for the interpreters compared to the controls, and this effect was greater in the right hippocampus.
Among the interpreters, language proficiency was related to increases in the right hippocampus and left superior temporal gyrus. Increases in the left middle frontal gyrus were related to teacher ratings of effort — those who put in the greatest effort (regardless of result) showed the greatest increase in this area.
In other words, both learning, and the effort put into learning, had different effects on brain development.
The main point, however, is that language learning in particular is having this effect. Bear in mind that the medical and cognitive science students are also presumably putting in similar levels of effort into their studies, and yet no such significant brain growth was observed.
Of course, there is no denying that the level of intensity with which the interpreters are acquiring a new language is extremely unusual, and it cannot be ruled out that it is this intensity, rather than the particular subject matter, that is crucial for this brain growth.
Neither can it be ruled out that the differences between the groups are rooted in the individuals selected for the interpreter group. The young people chosen for the intensive training at the interpreter academy were chosen on the basis of their talent for languages. Although brain scans showed no differences between the groups at baseline, we cannot rule out the possibility that such intensive training only benefited them because they possessed this potential for growth.
A final caveat is that the soldiers all underwent basic military training before beginning the course — three months of intense physical exercise. Physical exercise is, of course, usually very beneficial for the brain.
Nevertheless, we must give due weight to the fact that the brain scans of the two groups were comparable at baseline, and the changes discussed occurred specifically during this three-month learning period. Moreover, there is growing evidence that learning a new language is indeed ‘special’, if only because it involves such a complex network of processes and brain regions.
Given that people vary in their ‘talent’ for foreign language learning, and that learning a new language does tend to become harder as we get older, it is worth noting the link between growth of the hippocampus and superior temporal gyrus and language proficiency. The STG is involved in acoustic-phonetic processes, while the hippocampus is presumably vital for the encoding of new words into long-term memory.
Interestingly, previous research with children has suggested that the ability to learn new words is greatly affected by working memory span — specifically, by how much information they can hold in that part of working memory called phonological short-term memory. While this is less important for adults learning another language, it remains important for one particular category of new words: words that have no ready association to known words. Given the languages being studied by these Swedish interpreters, it seems likely that much if not all of their new vocabulary would fall into this category.
I wonder if the link with STG is more significant in this study, because the languages are so different from the students’ native language? I also wonder if, and to what extent, you might be able to improve your phonological short-term memory with this sort of intensive practice.
In this regard, it’s worth noting that a previous study found that language proficiency correlated with growth in the left inferior frontal gyrus in a group of English-speaking exchange students learning German in Switzerland. Is this difference because the training was less intensive? because the students had prior knowledge of German? because German and English are closely related in vocabulary? (I’m picking the last.)
The researchers point out that hippocampal plasticity might also be a critical factor in determining an individual’s facility for learning a new language. Such plasticity does, of course, tend to erode with age — but this can be largely counteracted if you keep your hippocampus limber (as it were).
All these are interesting speculations, but the main point is clear: the findings add to the growing evidence that bilingualism and foreign language learning have particular benefits for the brain, and for protecting against cognitive decline.
 Mårtensson J, Eriksson J, Bodammer NC, Lindgren M, Johansson M, Nyberg L, Lövdén M. Growth of language-related brain areas after foreign language learning. NeuroImage [Internet]. 2012 ;63(1):240 - 244. Available from: http://www.sciencedirect.com/science/article/pii/S1053811912006581
A study involving Chinese-English bilinguals shows how words with negative emotional connotations don’t automatically access native translations, while those with positive or neutral emotions do.
Here’s an intriguing study for those interested in how language affects how we think. It’s also of interest to those who speak more than one language or are interested in learning another language, because it deals with the long-debated question as to whether bilinguals working in their non-native language automatically access the native-language representations in long-term memory, or whether they can ‘switch off’ their native language and use only the target language memory codes.
The study follows on from an earlier study by the same researchers that indicated, through the demonstration of hidden priming effects, that bilinguals subconsciously access their first language when reading in their second language. In this new study, 45 university students (15 native English speakers, 15 native Chinese speakers, and 15 Chinese-English bilinguals) were shown two blocks of 90 word pairs. The pairs could have positive emotional value (e.g., honesty-program), negative valence (failure-poet), or neutral valence (aim-carpenter); could be semantically related (virus-bacteria; love-rose) or unrelated (weather-gender). The English or Chinese words were flashed on the screen one at a time, with a brief interval between the first and second word. The students had to indicate whether the second word was related in meaning to the first, and their brain activity was monitored.
The English and Chinese speakers acted as controls — it was the bilinguals, of course, who were the real interest. Some of the English word pairs shared a sound in the Chinese translation. If the Chinese words were automatically activated, therefore, the sound repetition would have a priming effect.
This is indeed what was found (confirming the earlier finding and supporting the idea that native language translations are automatically activated) — but here’s the interesting thing: the priming effect occurred only for positive and neutral words. It did not occur when the bilinguals saw negative words such as war, discomfort, inconvenience, and unfortunate.
The finding, which surprised the researchers, is nonetheless consistent with previous evidence that anger, swearing or discussing intimate feelings has more power in a speaker's native language. Parents, too, tend to speak to their infants in their native tongue. Emotion, it seems, is more strongly linked to our first language.
It’s traditionally thought that second language processing is fundamentally determined by the age of acquisition and the level of proficiency. The differences in emotional resonance have been, naturally enough, attributed to the native language being acquired first. This finding suggests the story is a little more complicated.
The researchers theorize that they have touched on the mechanism by which emotion controls our fundamental thought processes. They suggest that the brain is trying to protect us by minimizing the effect of distressing or disturbing emotional content, by shutting down the unconscious access to the native language (in which the negative words would be more strongly felt).
A few more technical details for those interested:
The Chinese controls demonstrated longer reaction times than the English controls, which suggests (given that 60% of the Chinese word pairs had overt sound repetitions but no semantic relatedness) that this conjunction made the task substantially more difficult. The bilinguals, however, had reaction times comparable to the English controls. The Chinese controls showed no effect of emotional valence, but did show priming effects of the overt sound manipulation that were equal for all emotion conditions.
The native Chinese speakers had recently arrived in Britain to attend an English course. Bilinguals had been exposed to English since the age of 12 and had lived in Britain for an average of 20.5 months.
 Wu YJ, Thierry G. How Reading in a Second Language Protects Your Heart. The Journal of Neuroscience [Internet]. 2012 ;32(19):6485 - 6489. Available from: http://www.jneurosci.org/content/32/19/6485
Those learning a new language benefit from making suitable gestures as they repeat new vocabulary, and this can even extend to gestures arbitrarily linked to abstract adverbs.
I always like gesture studies. I think I’m probably right in saying that they started with language learning. Way back in 1980 it was shown that acting out action phrases meant they were remembered better than if the phrases had been only heard or read (the “enactment effect”). Enacted items, it turned out, “popped out” effortlessly in free recall tests — in other words, enactment had made the phrases highly accessible. Subsequent research found that this effect occurred both for both older and younger adults, and in immediate and delayed recall tests — suggesting not only that such items are more accessible but that forgetting is slower.
Following these demonstrations, there have been a few studies that have specifically looked at the effect of gestures on learning foreign languages, which have confirmed the benefits of gestures. But there are various confounding factors that are hard to remove when using natural languages, which is why the present researchers have developed an artificial language (“Vimmi”) to use in their research. In their first study, as in most other studies, the words and phrases used related to actions. In a new study, the findings were extended to more abstract vocabulary.
In this study, 20 German-speakers participated in a six-day language class to study Vimmi. The training material included 32 sentences, each containing a subject, verb, adverb, and object. While the subject nouns were concrete agents (e.g., musician, director), the other words were all abstract. Here’s a couple of sample sentences (translated, obviously): (The) designer frequently shapes (the) style. (The) pilot really enjoys (the) view. The length of the words was controlled: nouns all had 3 syllables; verbs and adverbs all had two.
For 16 of the sentences, participants saw the word in Vimmi and heard it. The translation of the word appeared on the screen fractionally later, while at the same time a video appeared in which woman performed the gesture relating to the word. The audio of the word was replayed, and participants were cued to imitate the gesture as they repeated the word. For the other 16 sentences, a video with a still image of the actress appeared, and the participants were simply cued to repeat the word when the audio was replayed.
While many of the words used gestures similar to their meaning (such as a cutting gesture for the word “cut”), the researchers found that the use of any gesture made a difference as long as it was unique and connected to a specific word. For example, the abstract word “rather” does not have an obvious gesture that would go with it. However, a gesture attached to this word also worked.
Each daily session lasted three hours. From day 2, sessions began with a free recall and a cued recall test. In the free recall test, participants were asked to write as many items as possible in both German and Vimmi. Items had to be perfectly correct to be counted. From day 4, participants were also required to produce new sentences with the words they had learned.
Right from the beginning, free recall of items which had been enacted was superior to those which hadn’t been — in German. However, in Vimmi, significant benefits from enactment occurred only from day 3. The main problem here was not forgetting the items, but correctly spelling them. In the cued recall test (translating from Vimmi to German, or German to Vimmi), again, the superiority of the enactment condition only showed up from day 3.
Perhaps the most interesting result came from the written production test. Here, people reproduced the same number of sentences they had learned on each of the three days of the test, and although enacted words were remembered at a higher rate, that rate didn’t alter, and didn’t reach significance. However, the production of new sentences improved each day, and the benefits of enactment increased each day. These benefits were significant from day 5.
The main question, however, was whether the benefits of enactment depended on word category. As expected, concrete nouns were remembered than verbs, followed by abstract nouns, and finally adverbs. When all the tests were lumped together, there was a significant benefit of enactment for all types of word. However, the situation became a little more nuanced when the data was separately analyzed.
In free recall, for Vimmi, enactment was only of significant benefit for concrete nouns and verbs. In cued recall, for translating German into Vimmi, the enactment benefit was significant for all except concrete nouns (I’m guessing concrete nouns have enough ‘natural’ power not to need gestures in this situation). For translating Vimmi into German, the benefit was only significant for verbs and abstract nouns. In new sentence production, interestingly, participants used significantly more items of all four categories if they had been enacted. This is perhaps the best evidence that enactment makes items more accessible in memory.
What all this suggests is that acting out new words helps you learn them, but some types of words may benefit more from this strategy than others. But I think we need more research before being sure about such subtleties. The pattern of results make it clear that we really need longer training, and longer delays, to get a better picture of the most effective way to use this strategy.
For example, it may be that adverbs, although they showed the most inconsistent benefits, are potentially the category that stands to gain the most from this strategy — because they are the hardest type of word to remember. Because any embodiment of such an abstract adverb must be arbitrary — symbolic rather than representational — it naturally is going to be harder to learn (yes, some adverbs could be represented, but the ones used in this study, and the ones I am talking about, are of the “rather”, “really”, “otherwise” ilk). But if you persist in learning the association between concept and gesture, you may derive greater benefit from enactment than you would from easier words, which need less help.
Here’s a practical discussion of all this from a language teacher’s perspective.
 Macedonia M, Knösche TR. Body in Mind: How Gestures Empower Foreign Language Learning. Mind, Brain, and Education [Internet]. 2011 ;5(4):196 - 211. Available from: http://onlinelibrary.wiley.com/doi/10.1111/j.1751-228X.2011.01129.x/abstract
Two studies demonstrate that language development in young children with ASD is the same in those raised in a multilingual environment as in those raised with only one language.
Bilingual parents of children with autism spectrum disorder often decide to speak only one language around their child because of advice from child development professionals who believe that exposure to two languages might further limit the child’s communication skills. Two recent studies challenge that assumption.
One study tested the vocabulary size of 14 bilingual (English-Mandarin/Cantonese) and 14 English-monolingual young children with ASD (aged 3-6). Bilingual children had a larger total vocabulary than monolingual children. When translation equivalents (two words in each language with the same meaning) were counted only once, the vocabularies of both bilingual and monolingual children were not significantly different. Both groups had equivalent scores on all but one measure of language and vocabulary, including English production vocabulary, conceptual production vocabulary, and vocabulary comprehension.
The second Canadian study found similar results in a slightly larger group of children (45 bilingual and 30 monolingual children with an average age of around 5). Languages covered were diverse: French, English, Chinese, Farsi, Hebrew, Italian, Romanian, Spanish and Tamil. Bilingual children were divided into those who were exposed to both languages from infancy, and those who were exposed later (the cut-off was 12 months, but in general changes in the language environment occurred much later: on average, children in the former group were bilingually-exposed for the first 25 months; children in the latter group were monolingually-exposed for the first 31 months). Eleven children were trilingual. In order not to introduce sampler bias, non-verbal children were not excluded — seven participants spoke fewer than 10 words, of whom two were nonverbal.
There were no significant differences between the three groups at a language level, although monolingual and bilingual children exposed from infancy consistently scored higher than bilingual children exposed from a later age. Also, children exposed to two or more languages from infancy scored significantly higher than both groups on social interaction, and those exposed later were worst of the three groups. These differences probably reflect various social variables underlying the different language experiences.
The main reason for the belief that autistic children are better not ‘burdened’ with an additional language is because of their language difficulties. These studies are not saying that a child with ASD raised in two languages will be equally fluent with both. In the second study, second language vocabularies were much smaller than their dominant language vocabularies. But that’s not the point. Whether or not there is any general cognitive advantage in bilingualism for this group, as there is for normally-developing children, remains to be determined. But there is a clear message that parents of ASD children can take on board: if your family is bilingual, relax and enjoy interacting with your ASD child in your language of choice.
 Petersen JM, Marinova-Todd SH, Mirenda P. Brief Report: An Exploratory Study of Lexical Skills in Bilingual Children with Autism Spectrum Disorder. Journal of Autism and Developmental Disorders [Internet]. 2011 . Available from: http://www.springerlink.com/content/e23p3j601u11m024/
 Hambly C, Fombonne E. The Impact of Bilingual Environments on Language Development in Children with Autism Spectrum Disorders. Journal of Autism and Developmental Disorders [Internet]. 2011 . Available from: http://www.springerlink.com/content/9318n42233747147/
A study of Korean preschoolers demonstrates that at least some of the cognitive benefits of bilingualism are due to learning two languages, not because of a more diligent culture or a more enriched environment.
An increasing number of studies have been showing the benefits of bilingualism, both for children and in old age. However, there’s debate over whether the apparent benefits for children are real, or a product of cultural (“Asians work harder!” or more seriously, are taught more behavioral control from an early age) or environmental factors (such as socioeconomic status).
A new study aimed to disentangle these complicating factors, by choosing 56 4-year-olds with college-educated parents, from middle-class neighborhoods, and comparing English-speaking U.S. children, Korean-speaking children in the U.S. and in Korea, and Korean-English bilingual children in the U.S.
The children were tested on a computer-game-like activity designed to assess the alerting, orienting, and executive control components of executive attention (a child version of the Attention Network Test). They were also given a vocabulary test (the Peabody Picture Vocabulary Test-III) in their own language, if monolingual, or in English for the bilinguals.
As expected, given their young age, English monolinguals scored well above bilinguals (learning more than one language slows the acquisition of vocabulary in the short-term). Interestingly, however, while Korean monolinguals in Korea performed at a comparable level to the English monolinguals, Korean monolinguals in the U.S. performed at the level of the bilinguals. In other words, the monolinguals living in a country where their language is a majority language have comparable language skills, and those living in a country in which their primary language is a minority language have similar, and worse, language skills.
That’s interesting, but the primary purpose of the study was to look at executive control. And here the bilingual children shone over the monolinguals. Specifically, the bilingual children were significantly more accurate on the attention test than the monolingual Koreans in the U.S. (whether they spoke Korean or English). Although their performance in terms of accuracy was not significantly different from that of the monolingual children in Korea, these children obtained their high accuracy at the expense of speed. The bilinguals were both accurate and fast, suggesting a different mechanism is at work.
The findings confirm earlier research indicating that bilingualism, independent of culture, helps develop executive attention, and points to how early this advantage begins.
The Korean-only and bilingual children from the United States had first generation native Korean parents. The bilingual children had about 11 months of formal exposure to English through a bilingual daycare program, resulting in them spending roughly 45% of their time using Korean (at home and in the community) and 55% of their time using English (at daycare). The children in Korea belonged to a daycare center that did offer a weekly 15-minute session during which they were exposed to English through educational DVDs, but their understanding of English was minimal. Similarly, the Korean-only children in the U.S. would have had some exposure to English, but it was insufficient to allow them to understand English instructions. The researchers’ informal observation of the Korean daycare center and the ones in the U.S. was that the programs were quite similar, and neither was more enriching.
 Yang S, Yang H, Lust B. Early Childhood Bilingualism Leads to Advances in Executive Attention: Dissociating Culture and Language. Bilingualism: Language and Cognition [Internet]. 2011 ;14(03):412 - 422. Available from: http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8292914
A second study confirms the dramatic effect of being bilingual, with bilingual speakers being diagnosed with Alzheimer’s more than 4 years later than monoglots.
Clinical records of 211 patients diagnosed with probable Alzheimer's disease have revealed that those who have spoken two or more languages consistently over many years experienced a delay in the onset of their symptoms by as much as five years. It’s thought that lifelong bilingualism may contribute to cognitive reserve in the brain, enabling it to compensate for memory loss, confusion, and difficulties with problem-solving and planning.
Of the 211 patients of the Sam and Ida Ross Memory Clinic at Baycrest, 102 patients were classified as bilingual and 109 as monolingual. Bilingual patients had been diagnosed with Alzheimer's 4.3 years later than the monolingual patients on average, and had reported the onset of symptoms 5.1 years later. The groups were equivalent on measures of cognitive and occupational level, there was no apparent effect of immigration status, and there were no gender differences.
The findings confirm an earlier study from the same researchers, from the clinical records of 184 patients diagnosed with probable Alzheimer's and other forms of dementia.
 Craik FIM, Bialystok E, Freedman M. Delaying the onset of Alzheimer disease. Neurology [Internet]. 2010 ;75(19):1726 - 1729. Available from: http://www.neurology.org/content/75/19/1726.abstract
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