The Neural Mechanisms of Private Speech in Second Language Learners’ Oral Production: An fNIRS Study

• DOI: 10.3390/brainsci15050451
• Publication Date: 2025-04-29T11:49:36Z
• Authors: Rong Jiang; Zhe Xiao; Yihan Jiang; Xueqing Jiang

Background: According to Vygotsky’s sociocultural theory, private speech functions both as a tool for thought regulation and transitional form between outer inner speech. However, its role in adult second language (L2) learning—and the neural mechanisms supporting it—remains insufficiently understood. This study thus examined whether facilitates L2 oral production investigated underlying mechanisms, including extent which resembles regulatory function nature of Methods: In Experiment 1, identify natural users speech, 64 Chinese-speaking English learners with varying proficiency levels were invited complete picture-description task. 2, functional near-infrared spectroscopy (fNIRS) was used examine 32 identified 1. Results: 1 showed that production. 2 revealed elicited highly similar patterns connectivity. Among high-proficiency learners, exhibited enhanced connectivity network thought-regulation network, indicating involvement higher-order cognitive processes. contrast, among low-proficiency primarily restricted language-related regions, suggesting supports basic linguistic processing at early stages. Furthermore, stronger speech-related brain regions. Conclusions: is first by using fNIRS. The findings provide novel evidence serves scaffold bridging Its appears evolve increasing proficiency.