A new neuroscience study suggests that people who speak more than one language do not keep separate grammatical systems for each language. Instead, the brain appears to rely on one shared mechanism for processing grammar, challenging the long-held assumption that bilingualism means different systems for different tongues.
The research, published in JNeurosci, was led by Dr. Asti Blanco-Elorrieta of New York University and her colleagues. They studied 23 volunteers who speak both Spanish and English, using MEG, a highly sensitive technique that measures brain activity in thousandths of a second. While lying in the scanner, participants completed simple grammar tasks such as changing words from singular to plural.
The result was striking, the brain activity was nearly identical whether the task was done in English or Spanish. To make sure the brain was not simply recalling memorized answers, the researchers repeated the test with invented words, including “Ailos.” The response was the same, showing that the brain was not just retrieving vocabulary but actively applying grammar rules in real time.
The findings point to the left frontal region of the brain as the main area building sentences across languages. They also support a newer view of bilingualism, not as a burden on the brain, but as training that can strengthen and make neural networks more efficient, much like exercise strengthens muscles. Dr. Mirjana Bozic of the University of Cambridge, who was not involved in the study, called the results “elegant and convincing,” while asking whether the same mechanism works for languages that are much more different from one another, such as Hebrew and Chinese. That question is now one of the next challenges researchers want to answer.
