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As globalization takes down former barriers to trade, travel, migration and communication, the world is finding more needs for bilingualism. As we train more people in other languages, as there are more marriages between people from different countries, and as there are more children being raised in bilingual households, the processes that produce and sustain a bilingual brain are being examined more closely. Parallel to this interest in bilingual brains is a development in technology that allows us to examine functioning brains as they respond to different stimuli. These new tests have much to offer in exploring bilingual brains and they may reveal important findings that help the growing field of language instruction teach more effectively. While they will help increase our knowledge of bilingual brains, they will also undoubtedly open up new questions and areas of exploration.
The two newest and most significant technologies in regards to studying bilingualism are magnetic resonance imaging (MRI) and positron emission tomography (PET). MRIs "record the alteration in density of magnetic resonance signals produced by deoxyhaemoglobin, a substance needed by the brain metabolism" (1). Wernfrid Doell explains that PET scans
"measur[e] changes in brain metabolism.... [S]ubjects are injected with radioactive oxygen with a short half rate time which is then transported with the blood to brain regions that are in need of energy. The scanner records the changes in density of radioactive particles in the brain as subjects perform... tasks. As brain cells do not possess any energy storage they have to be constantly supplied by the bloodstream and therefore the measurement of changes in the regional cerebral blood flow... allows us to draw conclusions on the localization of brain processes" (1).
Using these two tests, researchers can analyze scans of the region of activity during experiments on participants; this data was unavailable before the advent of this technology.
One especially interesting and well-done study will help to highlight types of advances made possible by the new technology. H.S. Kim, with other researchers at Cornell University Department of Neurology and Neuroscience, used MRIs to investigate differences between early- and late-learning bilinguals: the first group had learned both languages in infancy and the second group had learned their second language in early adulthood (1). Participants performed a "sentence generation task" while being monitored. They were presented with graphic cues of morning, afternoon, and evening and instructed to silently recount the events of the previous day during that time (talking out loud involves too much movement to administer the MRI). Looking at Broca's and Wernicke's areas (discussed further later), researchers analyzed how much overlap and how much distinction there was between the two loci of activation in the brain.
Kim et al. found that in Broca's area "the overlapping area is much bigger for the early bilingual, whereas two adjacent but distinct cortical areas are activated for the late bilingual. In Wernicke's area Kim et al. "found overlapping areas of brain activation for both their test groups" (1). From these findings they suggest that language representation in Wernicke's area is less affected by the age of initial exposure than it is in Broca's area. Additionally, they found that there was differentiation among individuals (even those knowing the same languages) in the same learning groups. (For full description of this experiment and scans of bilingual brains, see (1)).
These findings are important in furthering our knowledge of where language is stored and what areas of the brain are given responsibility for what functions during lateralization. It is also important in exploring how this differs among individuals and between early- and late-learning bilinguals. Broca's area is located in the frontal lobe and is associated with the production of language, while Wernicke's area is in the temporal lobe and is more generally associated with the understanding of language (2). If there is more generally a difference found between early and late learners in Broca's area, and less of a difference in Wernicke's area, this may give us insight into different organizations of the brain's delegation of functions between the two groups. Kim et al.'s findings may suggest that when a second language is learned later in life, its method of production is located in an auxiliary position instead of being more incorporated into a single area as with early learners. Also, there has been evidence of a "critical period" of language learning that ends around the onset of puberty. Before this point, language acquisition appears to be more successful in terms of pronunciation and other signs of "native" use (3). This supports the significance of differences found by Kim et al. Though these are merely directions of exploration, instead of conclusions, they may help to spur more investigation into bilingual brains. These advances in technology not only help us to change how we think of bilingual teaching, but also help neurosurgeons gauge what the effects of tumor removal on language abilities will be and help us to understand bilingual aphasia and its recovery processes. ((1) and (2)).
As this technology advances and helps us to understand the location and processes of language production, how we teach and raise bilingual children will be affected. It will be important to look at what types of learning are most effective with young children. The effective use of television for language acquisition may depend on how interactive the experience is. Case studies cite the importance of exchange in language learning-- conversing with a child instead of speaking at her (4). Also, implementing language programs for very young children in order to take advantage of the "critical period" before puberty would increase the effectiveness of language instruction. This is especially important in helping the children of immigrants prepare for school and in avoiding students graduating from bilingual programs still unable to speak English (5) and (6). During this "critical period," between the ages of 1 1/2 and 6 years, children learn around nine words per day (4); if this learning leap could include a second language, the effectiveness of education could be drastically increased. The benefits of leaning a second language are impressive. Betty Birner cites the benefits of learning a second language as improved cognitive development, maintenance of a child's cultural identity, an advantage in the global market place and the encouragement of cross-cultural awareness and understanding (5). If technology could encourage these developments it would be an immense contribution to our global society.
In further exploring the brain with PETs, MRIs and other technology, there are many paths of discovery that open up to us. Researching the effect of teaching, parenting and care-taking on learning will be more easily done with these scans. Discerning the effects of and processes of recovery for brain aphasia will be greatly assisted by the new research being done on brain structure and activity. This technology will also assist neurosurgeons in minimizing the disruption to language capabilities when removing brain tumors. In all of the ways that it will enlighten us about brain function, these new technologies will help advance our society in this age of globalization and multilingualism.
2) Boston Globe article on bilingualsim ,
3) Acquisition of English as a Second Language,
4) Infant Dual Language Acquisition Revisted,
6) NY Times article, Improving Bilingual Education,
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