A study on word learning recently published in Neuropsychologia is shedding light on the age-old question of how language learners’ minds store the target language.
Researchers at the Pontifical Catholic University of Chile found that new words in the native language and the target language are stored in largely overlapping regions of the brain; however, L2 words triggered more activity in the primary auditory cortex, suggesting increased phonological processing efforts.
“Our results shed new light on the neural representation of two languages in the bilingual brain, by examining newly learned words that participants had no prior experience with,” the paper reads.
As the researchers point out in the paper, research on bilingualism has long sought to better understand how two languages are represented in the brain—either as one single language system or as two separate systems. To investigate this question with regard to the lexicon (as opposed to other aspects of language learning, such as grammar rules or orthography, for example), the researchers conducted fMRI scans on 20 bilingual speakers of Spanish and English during a semantic categorization task.
The study focused on the acquisition of unfamiliar lexical items in both the native language (Spanish) and the second language (English), by presenting made-up nonsense words (half of which were phonotactically similar to Spanish words while the other half were similar to English words) to the participants during a training session and having them associate each word with a specific semantic meaning, as if they were learning genuinely new vocabulary items.
After two training sessions in which the new words were memorized, participants performed a vocabulary test (including both the new words and a set of familiar real words) while an MRI scanner measured their brain activity. For the most part, overlapping regions of the brain were activated during the task; however, portions of the brain involved in speech processing were more active for the English (L2) cues, indicating that the brain is attuned to the phonological differences between the native language and the target language.