There is increasing evidence that bilingualism can affect the functioning of the brain. Older, lifelong bilinguals demonstrated better cognitive abilities in tasks requiring increased cognitive control.
These cognitive effects are most pronounced in bilingual people who speak two languages in their daily lives compared to those who speak a second language but do not use it frequently. Our new research has drawn attention to structural improvements in the brain that are now observed in people who are bilingual immersed themselves in bilinguals.
Bilingualism for children affects both the main types of brain tissue and the structure of the brain, including gray matter and white matter. The neurons in our brain have two different anatomical features: the cell bodies where all information, thinking and planning processes take place, and their axons, which are the main pathways that connect brain areas and transfer information between them.
Cell bodies are organized around the surface of the brain – gray matter – and all axons converge beneath it and connect to white matter.
We call it white matter because axons are wrapped in a fatty layer of myelin that allows for better neuronal communication – the transfer of information around the brain. Myelin acts as an "insulation" that prevents it from "leaking" from the axon during transmission.
Does language learning restructure the brain?
One way that white matter can become more efficient is to increase its “isolation,” myelin, allowing information to be transferred faster and with less loss. Older lifetime bilinguals, young early bilinguals, and adult early bilinguals have been shown to exhibit greater integrity or thickness of myelin – known as “myelin” – compared to monolinguals. Some researchers have even suggested that lifetime experience of bilingualism preserves myelination (or integrity) of white matter from natural deterioration in old age.
Based on these recommendations, our research sought to explore whether similar effects to white matter would be seen in late bilinguals compared to monolinguals in the same item and education. We defined “late bilinguals” as people who learned their second language around the age of 10. Current research on late bilinguals has also shown changes in white matter structure during second language instruction, but the second language is not actively used.
What happens to the white matter?
Research has suggested that bilinguals with late immersion show changes in gray matter structure and processing of their second language similar to native English speakers. Therefore, we predicted that the effect of tongue immersion would be similar to white matter for our bilinguals.
This is exactly what we found: compared with monolingual adults of similar age, our bilinguals showed greater white matter integrity in parts of the brain involved in language processing. This closely corresponded to the effects on the brain for early and older bilinguals.
What is the immersion method?
Our findings also support the idea that bilingualism “reshapes” the brain, while also showing that bilingual immersion is an important factor. In other words, it is possible that the better preservation of brain structure reported in older bilinguals is an effect of continued bilingual use rather than early language acquisition or lifelong bilingualism.
In conclusion, any effect of bilingualism on the structure of white matter in the brain does not appear to be independent of the critical periods when people learn a language. While it is possible that there is a link between increased connectivity between brain regions and the cognitive benefits reported in bilinguals the earlier the child language course is, our study did not test this and is worthy of future research.
This is the philosophy behind Qkids English Learning Programme methodology and its surrounding references.