Anyone who learned a foreign language in high school knows that you spend a lot of time translating the things you see and hear from your native language to the foreign language and back. But what if you have two native languages?
My mother is bilingual. She speaks both Spanish and English fluently, without accent and, according to her, without translating back and forth. She has been bilingual since she could talk, developing both Spanish and English language at the same time, around the age of one. My grandparents report that she never treated the two languages as the same language. She also never mixed the two languages and she never spoke the wrong language to the wrong person.
Is there a difference in the brain activity of bilinguals who are bilingual at an early age, say five years old, compared to people who learn a language in early adulthood and beyond? Is my mom’s brain different from my own? According to one study, the answer is yes.
Participants in this study, which was conducted in Los Angeles, were Spanish-English bilinguals who had mastered both languages by the age of ten. There were 12 participants studied. In all cases, the participants were native Spanish speakers who were exposed to English at the age of 5. In all cases, the adult participants were in their twenties and tested as English-Language dominant, meaning that testing identified their dominant language as English.
During the study, participants were asked to name pictures. The prompt was given in either English or Spanish (“say” or “diga”) and the person was supposed to reply in the language of the prompt. The pattern of the prompt was changed during each set. Sometimes the languages alternated. Other times, the language was kept constant. Researchers wanted to know what happened in the brain when bilinguals were asked to switch languages frequently.
Studies have shown that early Spanish-English bilinguals show little evidence of separate neural systems for each language. In other words, they don’t translate in their heads.
The theory was, then, that they operated as if everything was all one language.
However, during the picture name game there was increased activity in Dorsolateral Prefrontal Cortex when switching between languages. The Prefrontal cortex is the region of the brain that works with long-term memory tasks, not language. It is not normally associated with language functions. The parietal lobes which control the reception and correlation of sensory information were very active as well.
The single-language tests revealed differences in areas used for language processing.
When the test required them to switch languages there was activity, not just in language centers, but also in areas of the brain involving memory, emotion, and feeling.
This finding suggests that early bilinguals involve more areas in the brain than just the language centers when manipulating two languages. While this finding is interesting, I would like to see more research done. There were only twelve subjects. They are all bilingual starting at of the age of 5. What if the person is bilingual from birth, like my mother?
Would that make a difference? Would her brain operate more like a mono-lingual or like a bilingual brain?
This is relevant to therapy for brain injury. If an early bilingual person has a stroke that impacts language, do they have a higher chance of recovery because they use more of their brain for language? This is where I think the research should go next.
Hernandez, A. E. (2009). Language switching in the bilingual brain: What’s next? Brain and Language, 109(2-3), 133-140. Doi: 10.1016/j.bandl.2008.12.005