Researchers from Spain's Basque Center on Cognition, Brain and Language (BCBL) have uncovered distinct specialization in brain regions during adult language learning. Their findings, published in the Journal of Neuroscience on November 9, 2020, highlight the brain's remarkable plasticity in language systems.
Human language is a uniquely complex ability, balancing cerebral plasticity with neuronal specialization—core principles of brain organization. By examining adult language acquisition, experts gain deeper insights into these mechanisms. The BCBL study reveals that the brain's hemispheres contribute differently in adults compared to native language learning from birth.
Language typically engages the fronto-temporo-parietal network, predominantly on the left side for 95% of people. The right hemisphere provides support, compensating if the left is damaged.
Using functional magnetic resonance imaging (fMRI), the researchers observed activity in both hemispheres as adults read and spoke in their native language and the new one. Initially, the two languages activated similar brain areas, which then differentiated over time.
The left hemisphere handles language production for both native and new languages. However, comprehension (listening and reading) shows flexibility: native language understanding stays left-lateralized, while the new language engages the right hemisphere.
These results indicate that language production is firmly rooted in the left hemisphere, but comprehension is more adaptable. This explains why adults often find speaking a new language harder than understanding it. The study enriches ongoing debates about the brain's language organization with fresh evidence.
