Language lateralisation in late proficient bilinguals: a lexical decision fMRI study

Area of Science:

• Neuroscience
• Cognitive Science
• Linguistics

Background:

• Over half the global population are bilingual.
• Research is crucial to understand the neural basis of language organization in bilinguals.
• Key questions address whether second language (L2) processing uses the same neural mechanisms as first language (L1) processing.

Purpose of the Study:

• To investigate language processing in late proficient bilinguals.
• To compare neural network activation between bilinguals and monolinguals.
• To examine differences in brain activation during L1 and L2 processing.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed.
• A lexical decision task with five conditions was used.
• Eight late proficient bilinguals and matched monolingual controls participated.

Main Results:

• Bilinguals exhibited greater bilateral activation for both L1 and L2 compared to monolinguals.
• Bilinguals showed weaker language lateralization.
• Increased overall brain activation was observed in bilinguals, particularly during L2 processing.

Conclusions:

• Late proficient bilinguals, especially those immersed in an L2 environment, recruit more extensive neural networks than monolinguals.
• Bilingualism influences the neural organization of language.
• The findings contribute to understanding the cognitive and neural adaptations associated with bilingualism.