Introduction
This page is the fourth part of a study of articles.
Beyond Bilingualism: multilingual experience correlates with caudate volume By Alexis Hervais-Adelman, Natalia Egorova, Narly Golestani
2nd language acquisition and bilingualism at an early age and the impact on early cognitive development by ELLEN BIALYSTOK
Cognitive advantages and disadvantages in early and late bilinguals by Sabra D. Pelham and Lise Abrams
Context
Multilingualism seems to have many advantages and disadvantages.
This is probably due to the different organisation of languages in the brain.
In this final part, we will be looking at
The changes in the brain linked to multilingualism.
Many models have been suggested to explain the brains’ structure and functions in multilinguals.
Some from a psychological perspective :
- Bilingual interaction model
- Revised hierarchy model
Others from a neuroscientific point of view :
- Adaptive control hypothesis
However, as the brain is extremely complicated and far from being fully understood, no single one explains the whole story.
Brain imaging
Brain imaging studies have been able to find interesting results too.
In bilinguals, the brain regions used in the processing of 2 different languages, overlap.
Late bilinguals were also found to use more regions in their less proficient language.
The brain regions used in language processing are areas controlling language and areas controlling executive functions. Many of the areas controlling language are also involved in cognitive control processes.
These areas and the functions related to them seem to explain the so called “bilingual advantage” outside of language ( such as in executive or cognitive tasks ).
Many of these areas, when comparing monolinguals and bi/multiliniguals are bigger or more dense.
For example, many areas of grey matter such as the ACC ( anterior cingulate cortex ), putamen, cerebellum, caudate and thalamus in addition to several white matter areas and brain networks have shown significant differences.
Putamen
Involved in suppression that enables the use of the appropriate language
Caudate
Involved in the management of lexical-semantic sets
These differences are dependent on the proficiency of both or all languages. They are also reliant on the age of acquisition of the non native languages but to a smaller degree.
The correlation of changes in the brain and age of acquisition may be because of the way the language is learned.
The author of the first article suggests that language is learned more implicitly at a young age and more explicitly when older.
However, the age of acquisition had no effect on the volume of the caudate, suggesting the effect of the age of acquisition or proficiency may be different depending on what the area is involved in regarding language.
Summary
Overall, being able to speak several languages has both many advantages and disadvantages regardless of the age at which someone starts to learn. The advantages seem to overweigh the disadvantages in many aspects : social, language and executive.
Knowing that our brains can become distinct from others by learning a new language is very exciting to know.
Many articles and experiments have been written and done in this field but with still so much to learn.
It would be even more interesting for example to know how the brain organises several languages, are all languages given a specific network even for speakers of 3 or 4 or even more languages ?
What other non language related skills and abilities could multilingualism have an effect on ?
These are a few of the so many questions left to answer…
Part 1 : The problems of multilinguals
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