A recent study led by University College London neuroscientist Cathy Price reveals how the human brain is uniquely adapted to manage multiple languages.
Language is processed in various regions of the left cerebral hemisphere. Previous studies using functional magnetic resonance imaging (fMRI) data showed that bilingual people activate the same general brain areas no matter what language they use. But Price's new experimental method, which involved measuring brain activity after showing subjects word pairs with similar meaning, showed increased activity in a specific region--the left caudate--when speakers shifted from one language to the other.
The new fMRI data clarifies why bilinguals with damaged left caudates involuntarily switch languages when speaking. The study is an important step in understanding how humans can speak more than one language, a unique ability of our complex brain.