Cognition and Behavior: Neural Signatures of Hierarchical Linguistic Structures in Second Language Listening Comprehension

Abstract

Native speakers excel at parsing continuous speech into smaller elements and entraining their neural activities to the linguistic hierarchy at different levels (e.g., syllables, phrases, and sentences) to achieve speech com-prehension. However, how a nonnative brain tracks hierarchical linguistic structures in second language (L2) speech comprehension and whether it relates to top-down attention and language proficiency remains elu-sive. Here, we applied a frequency-tagging paradigm in human adults and investigated the neural tracking re-sponses to hierarchically organized linguistic structures (i.e., the syllabic rate of 4 Hz, the phrasal rate of 2 Hz, and the sentential rate of 1 Hz) in both first language (L1) and L2 listeners when they attended to a speech stream or ignored it. We revealed disrupted neural responses to higher-order linguistic structures (i.e., phrases and sentences) for L2 listeners in which the phrasal-level tracking was functionally related to an L2 subject’s language proficiency. We also observed less efficient top-down modulation of attention in L2 speech compre-hension than in L1 speech comprehension. Our results indicate that the reduced d -band neuronal oscillations that subserve the internal construction of higher-order linguistic structures may compromise listening compre-hension in a nonnative language.