Neuroscientific research has shed light on the neurological underpinnings of bilingualism (fluency in two languages), compared to monolingualism (fluency in one language only).
Neuroplasticity (the changing of connections within the nervous system) is a huge difference between monolingual and bilingual brains. Recent technological advancements in MRI mean that scientists can visually observe the differences in neuroplasticity between monolingual and bilingual brains. In MRI, grey matter can be observed in the brain, which consists of cell bodies and dendrites (components of neurons). New connections and pathways are formed in the brain according to John Grundy (a neuroscientist at Iowa State University). The bilingual brain has denser grey matter, therefore more neuronal cell bodies and dendrites.
There are also white matter differences between monolingual and bilingual brains, with there being more white matter integrity in the bilingual brain. White matter consists of nerve fibers connecting different brain regions to allow for effective communication. These connections are maintained through regular practice and speech of the two or more languages spoken.
There is evidence to suggest that speaking more than one language acts as a protective mechanism against certain neurodegenerative conditions such as dementia. It is often viewed as ‘exercise’ for your brain. This is because the connections are becoming stronger over time.
A 2013 study at the University of Edinburgh concluded that bilingualism has a deep impact on the structures and processes within the brain. They had 648 participants from India, 391 who were bilingual. The bilingual subjects developed dementia 4.5 years later than the monolingual subjects.
For most people, the native language is stored in the left hemisphere of the brain where key language areas such as Broca’s area and Wernicke’s area are located. Scientists maintain that although language learning is a complex process, it does involve the exchange of information between the left and right hemispheres via the corpus callosum. The white matter volume and number of fibers of the corpus callosum, the gateway from the left to the right hemisphere, increases with bilingualism. This increases cortical connectivity in the brain, as well as highlighting how these regions are sensitive to variations in language experience.
Dr Ping Li (a professor of Psychology and Linguistics at Pennsylvania State University) showed that the anterior cingulate, a brain area responsible for conflict monitoring, is larger for bilingual people. This is because it can prevent other languages intruding on speech whilst monitoring the language. Bilinguals also use the anterior cingulate more efficiently than monolinguals to regulate nonlinguistic cognitive conflicts. The bilingual brain has been shown to better resolve cognitive conflicts in tasks, such as feeling unsure about the word for something in the second language.
Language learning also has numerous benefits outside of neuroscience, such as improved creativity, more powerful memory and stronger verbal and written communication skills.
It is clear that bilingualism has numerous benefits on the brain, particularly acting as a protective factor for neurodegenerative conditions. These findings may also influence educational and social policies, to perhaps enhance language-learning in schools.