Neural substrates of L2-L1 transfer effects on phonological awareness in young Chinese-English bilingual children

• Published in: NeuroImage (Orlando, Fla.) Vol. 291; p. 120592
• Main Authors: Kou, Jia-Wei, Fan, Li-Ying, Chen, Hsin-Chin, Chen, Shiou-Yuan, Hu, Xiaosu, Zhang, Kehui, Kovelman, Ioulia, Chou, Tai-Li
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.2024; Elsevier Limited; Elsevier
• Subjects: Bilingual education; Bilingualism; Brain; Brain research; Children; Children & youth; Chinese languages; Cognitive ability; Cognitive load; Development; Dyslexia; Elementary education; fNIRS; Hemispheric laterality; Infrared spectroscopy; Language instruction; Lateralization; Learning; Learning transfer; Linguistics; Literacy; Medical imaging; Monolingualism; Neural networks; Neuroimaging; Phonemes; Phonological awareness; Phonological processing; Phonology; Reading; Second language learning; Skills; United States > US; China; Taiwan; Learning; Development; Phonology; Bilingualism; fNIRS
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2024.120592

•Examine young bilinguals with distant languages (L1: Chinese and L2: English).•The early literacy transfer between L1 and L2 in an L1-dominant environment.•Use functional near-infrared spectroscopy to study transfer on phoneme awareness.•The L2 transfer on the left dorsal neural pathways with phonological processing.•The L1 transfer on the right frontal regions with increased cognitive load. The growing trend of bilingual education between Chinese and English has contributed to a rise in the number of early bilingual children, who were exposed to L2 prior to formal language instruction of L1. The L2-L1 transfer effect in an L1-dominant environment has been well established. However, the threshold of L2 proficiency at which such transfer manifests remains unclear. This study investigated the behavioral and neural processes involved when manipulating phonemes in an auditory phonological task to uncover the transfer effect in young bilingual children. Sixty-two first graders from elementary schools in Taiwan were recruited in this study (29 Chinese monolinguals, 33 Chinese-English bilinguals). The brain activity was measured using fNIRS (functional near-infrared spectroscopy). Bilingual children showed right lateralization to process Chinese and left lateralization to process English, which supports more on the accommodation effect within the framework of the assimilation-accommodation hypothesis. Also, compared to monolinguals, bilingual children showed more bilateral frontal activation in Chinese, potentially reflecting a mixed influence from L2-L1 transfer effects and increased cognitive load of bilingual exposure. These results elucidate the developmental adjustments in the neural substrates associated with early bilingual exposure in phonological processing, offering valuable insights into the bilingual learning process.