Articles and Stories

October 18, 2012

We all admire people who speak two or more languages and can switch from one language to another without having to think or translate first. What happens in the brain of bilingual people? Does being bilingual have other advantages than being able to communicate in more than one language?

New research into the neurobiology of bilingualism has found that being fluent in two languages, particularly from early childhood, not only enhances a person’s ability to concentrate, but might also protect against the onset of Alzheimer’s dementia and other age-related cognitive decline.

Until fairly recently, many parents were afraid to expose children to a second language at an early age believing that it might not only delay the child’s language skills but harm their intellectual growth. New research, however, has found that bilingual children reach language milestones at the same age as monolingual children, and they do not display any evidence of being confused by their languages.

To the contrary, being bilingual may give children an extra advantage. Bilingual preschoolers have been found to be better at focusing and tuning out distractions than their monolingual peers. The same similar ability to concentrate has been found in bilingual adults, who became fluent in two languages at an early age. It may be that managing two languages helps the brain sharpen and retain its ability to focus while ignoring irrelevant information.

Other research suggests that bilingualism may delay the onset of age-related dementia, including Alzheimer’s disease, by up to four years. The reason behind that is not known yet, but some theorize that speaking two languages may increase blood and oxygen flow to the brain and keep nerve connections healthy, factors believed to help delay the onset of dementia.

More recently, scientists have discovered that bilingual adults have more gray matter in the brain’s left hemisphere, where most language and communication skills are controlled. The effect is strongest in people who learned a second language before the age of five and in those who are most proficient at their second language. This finding suggests that being bilingual from an early age significantly alters the brain’s structure.

Exactly how the brain organizes language in bilingual individuals has been debated and researched for many years. Is each language “stored” in its own area of the brain or does it overlap certain regions? Scientists in brain imaging recently discovered that the processing of different languages occurs in much of the same brain tissue.

However, when people are rapidly speaking back and forth between their two languages, so to say, in “bilingual mode”, they show significantly more activity in the right hemisphere of the brain than monolingual speakers, particularly in a frontal area called the dorso-lateral prefrontal cortex (the source of the bilingual advantages in attention and control). This activity is so prominent on brain scans that it serves as a “neurological signature” for bilingualism.

Neuroscience research is also showing promise for treating bilingual patients who lose the ability to produce or understand speech after a brain injury by using both languages. Rehabilitation efforts that use these two languages hold a greater promise for recovery than when only using one language.