Second Language Acquisition and Brain Function

Introduction

Language is central in human beings lives in communicating in their society and even globally. To know a language is more than knowing the composition of its formation as it involves the knowledge of the way it functions. According to Sakai (2005), language acquisition is among the most fundamental trait of an individual which occurs due to the developmental changes of the brain. Both the structure and the function of the brain can be changed by experience. Therefore the experience of learning a second language is most probably accompanied by brain changes.

Language Acquisition

Sakai (2005) explains that during language acquisition years, the brain does not solely store linguistic information, but it also adjusts to a language grammatical regularity. Within a few years of a child’s life, he or she acquires natural language with no analytical thinking aid, and also without obvious instructions of grammar especially from schools. Therefore, grammatical rules origin should be ascribed to a human brain’s innate system. The competence and the knowledge of human language can be acquired by various modality types and means. Linguistics regards languages, sighing and speaking comprehension as language primary faculties, that is inherent or innate and biologically determined while writing and reading are regarded as secondary abilities.

Structural Brain Changes

Inferior Parietal Region

Noort, Bosch and Hugdahl (2006) explain that structural MRI has been used recently in second language research. Structural MRI is a useful complimentary approach and not a competing technique in second language learning. The researchers explain that voxel-based morphometry was used in investigating structural plasticity in healthy right-handed Italian and English bilinguals. In testing the differences in the density of white and grey matter between monolinguals and bilinguals, they recruited 25 “early” bilinguals, who had learnt a second European language before they were five years and were practicing the language regularly, 25 monolinguals who had had no or little exposure to as second language, and 33 late bilinguals who learnt the second language between ten and fifteen years and continued practicing it for at least five years.

Voxel-Based Morphometry

Voxel-based morphometry study reveals that the inferior parietal cortex grey matter is greater in bilinguals than monolinguals. This increased grey matter was evident in both early and late bilinguals but early bilinguals had a greater effect in both right and left hemispheres (Noort, Bosch, & Hugdahl, 2006). The authors, (Noort, Bosch, & Hugdahl, 2006) also identified that increase in the grey matter density in the bilinguals’ left inferior parietal cortex relative to monolinguals, is that in early bilinguals it is more pronounced than in late bilinguals. It also shows that the density in the left inferior parietal cortex increases with the proficiency of second language and decreases as acquisition age increases. The effects are as a result of structural reorganization induced by experience or genetic predisposition to elevated density.

Studies reveal that early bilinguals acquire a second language from social experience instead of genetic predisposition (Noort, Bosch, & Hugdahl, 2006). Therefore, the human brain structure is changed by second language acquiring experience. The, structural changes of human brain occurs in response to environmental demands as a learning function in spheres other than language. Therefore, the relationship between grey matter performance and density is an example of more common principle of structure-function extending beyond the language domain.

The Corpus Callosum

This is another area where structural differences between bilinguals and monolinguals learners are found. The human brain goes through cortical adaptation in accommodating multiple languages either by creating new cortical networks in the cortex distinct adjacent areas or recruiting existing regions used by the native language in handling certain L2 functional aspects. However, regardless of how circuitry is organized by the cortex in handling multiple languages, all behaviors of non-reflexive, including communication and cognition results from unconsciousness and activity seamless coordination between the two hemispheres through the cerebral commissures (Noort, Bosch, & Hugdahl, 2006).

According to Noort, Bosch and Hugdahl (2006), corpus callosum is the main fiber tract connecting both brain hemispheres and in humans it approximately has 200-350 million fibers. Language areas fibers in the superior temporal gyrus pass through the corpus callosum isthmus. Also the corpus callosum body is involved in the process of language. The learning of new language is supported by the prominent growth in language cortex which is the key maturation phase in the brain region for this factor. Thus corpus callosum structural changes take place in the second language acquisition process.

Critical Period

Acquisition age plays a major role in acquisition of second language. The rule of thumb “earlier is better” captures the negative correlation between eventual asymptotic performance and onset of age of learning. If second language acquisition is limited by critical period, it is expected that performance linguistic negatively correlates with the age at which second language begins.

How the Brain Makes Way for a Second Language

 In an article by Brain Connection (2016) functional magnetic resonance imaging, fMRI, were used in a study to determine how the human brain represent multiple languages. The Broca’s area according to the study spatially separates native and second languages. Broca is the region at the frontal brain lobe which is responsible for the language movement motor parts in the palate, tongue and the mouth. In contrast, the native and second languages have a little separation in the Wernicke’s area which is the area at the brain’s posterior temporal lobe that is in control of language comprehension.

The fMRI Studies

Brain Connection (2016) explains that fMRI studies suggest that the adult learners with difficulties in learning second language do not lack understanding of second language words, but they lack the motor skills to form the words in the tongue and the mouth. This explains the reason why second language learners often comprehend the questions they are asked using a new language but they fail to form quick response. This study (Brain Connection, 2016) also explain that bilinguals who learns a language earlier in life easily speaks the two languages as easily as comprehending  when both languages are spoken to them. These early bilingual learners lack separation in either Broca’s or Wernicke’s areas for both languages which is an indication that in terms of brain activation, their ability to process both languages is controlled by the same brain region.

According to Brain Connection (2016), the fMRI studies in children suggest that second languages that are learnt early in a child’s life are not processed separately in the brain. The brain language areas go through the greatest growth dynamic between the age of 6 and 13. This is in contrast to the “first three years” child development idea which in past years has been receiving much press. According to this article, middle and elementary school years are the most biologically advantageous times for second language acquisition. The neuroscience studies are a suggestion that the brain is a plastic entity. The most biologically advantageous method that an individual can acquire a second language is a combination of vocalization and listening both in children and adults.

The process by which an adult learns a second language is different from that of a child because adults already have cues of comprehending new languages based on the principles of their mother tongue. Using a cognitive perspective, the inter-language concept explains the mental process that is responsible in the acquisition of second language: the interconnected system characteristics series that a learner progresses over time and the internal system constructed by a learner at a point in time. Therefore, inter-language theory acts as the first attempt in explaining the acquisition of second language.

Inter-Language Theory

According to the inter-language theory, there are five L2 acquisition processes: generalization of rules and principles, L2 communication strategies, strategies of second language learning, transfer of training and language transfer. In relation to first language and second language transfer mechanisms, both negative and positive transfers are born in mind but they lack to function according to similar rules; knowledge of L1 and L2, age, and other variables which influence the abilities of learning transfer. In regard to generalization principles, inter-language elements results from clear overgeneralization of target language sematic features and rules.

Acquisition and Processing of L2 Grammar

During the formation of concepts, the mind categorizes stimuli. For example a young baby of four months have categorized varieties  of phonemes and sounds from his or her mother tongue making him/her ready of acquiring an acoustic image of words. Abutalebi (2008) explains that the cognitive system that mediates the words meaning is common in all languages. Conversely, based on the assumption of a sensitive or critical period for language acquisition, it is evident that the syntax language knowledge learnt after a critical period is differently represented than in L1. An L1 is implicitly generally acquired while an L2 it is learnt during a critical period, it is explicitly acquired due to the sense that its grammar is taught.

Therefore, the process that is involved in producing and perceiving sentences and words remains inaccessible to conscious awareness but persons may still contain grammar declarative knowledge in one way or the other. According to psycholinguistics, through the early stages of acquisition of second language, there may be dependency of first language in mediating the access of the meaning for second language lexical items. If the proficiency of L2 is increased, the dependency on L1 is reduced. Higher levels of L2 proficiency produces a mental representation of lexical sematic that closely resembles those that L1constructs and with majority of qualitative differences L2 and native speakers disappearing as proficiency increases (Abutalebi, 2008).

References

Abutalebi, J. (2008). Neural aspects of second language representation and language control (1st ed., pp. 466-478). Milan: Acta Psychologica. Retrieved from http://www.brainresearch.us/Nerural_Aspects_of_Second_Language_Representation_and_Language_Control.pdf

Brain Connection,. (2016). How the Brain Learns a Second Language. Brain Connection. Retrieved from http://brainconnection.brainhq.com/2001/01/27/how-the-brain-learns-a-second-language/

Noort, M., Bosch, P., & Hugdahl, K. (2006). Looking at Second Language Acquisition from a Functional- and Structural MRI Background (1st ed., pp. 2293-2299). Retrieved from http://csjarchive.cogsci.rpi.edu/proceedings/2006/docs/p2293.pdf

Sakai, K. (2005). Language Acquistition and Brain Development (1st ed., pp. 814-821). ScienceMAG. Retrieved from https://mambo.sites.ucsc.edu/wp-content/uploads/sites/158/2015/03/Language-Acquisition-and-Brain-Development-by-Kuniyoshi-L.-Sakai.pdf