Simultaneous and sequential bilinguals: Cross domain benefits as measured by behaviour and resting-state functional magnetic resonance imaging

The aim of the present investigation is to explore differences in the bilingual language learning experience based on age of second language acquisition, which fundamentally shapes the way language is represented in the brain and the abilities of the speaker. The question asked here is whether there is a "simultaneous bilingual advantage" when learning a new foreign language due to the attainment of two languages within a highly sensitive period in brain development, and whether there is transfer of any advantage to the music domain. Two groups of bilinguals were compared: 10 simultaneous bilinguals, who learnt both English and French from birth, and 11 sequential bilinguals, who learnt French from birth and English after the age of 7 years. All were highly proficient in both English and French, had no experience in a third language, nor exposure to the languages used in the experiment, and participants had no musical training. Participants were tested on new foreign speech perception and production tasks in Hindi and Farsi and were tested on comparable music perception and production tasks. They also completed a resting-state functional magnetic imaging scan to investigate intrinsic functional brain connectivity networks. Whereas the simultaneous bilinguals significantly outperformed their late-trained counterparts on the foreign speech perception task, the discrimination of the Hindi dental retroflex contrast, the two groups did not differ on the foreign speech production tasks (Hindi and Farsi), or music production tasks, and the sequential bilinguals performed significantly better on a music perception task. The results suggest that the advantage observed behaviorally in the simultaneous compared to the sequential bilinguals is confined to speech perception, and that simultaneous and sequential bilingualism might have different effects on auditory perception abilities as a result of different language acquisition circumstances. In addition, using the behavioural score on the Hindi discrimination task, simultaneous bilinguals who showed better performance on the task also displayed greater brain functional connectivity between the left temporoparietal junction and the right planum temporale, and between right Heschl's gyrus and the left supramarginal gyrus. Both the behavioural and imaging results suggest that linguistic experiences during the first year of life, when brain circuitry is undergoing crucial development, impact language perceptual learning abilities and brain functional organization. Simultaneous acquisition of two languages appears to confer an advantage later in life for perceiving the sounds of a new foreign language. In the larger context, this study adds to the body of knowledge about second language acquisition, its impact on behaviour and the brain, and the findings could have implications for language education.%%%%Le but de cette etude est d'explorer les differentes experiences d'apprentissage bilingue du langage en lien avec l'âge d'acquisition de la deuxieme langue, qui a une influence…