Quantity Convergence, Quality Divergence: Disentangling Fluency and Accuracy in L2 Mandarin Prosody

2026-02-26

AI Summary

This study investigates the dissociation between syntactic competence and prosodic realization in second language (L2) speech. Drawing on the BLCU-SAIT corpus, it compares oral productions from 67 native Mandarin speakers and 67 highly proficient Vietnamese L2 learners, integrating C-ToBI prosodic boundary annotation with dependency-based syntactic analysis. Findings reveal that while learners approximate native-like numbers of prosodic boundaries, their syntactic-to-prosodic mapping patterns diverge significantly, exhibiting a nonlinear acquisition trajectory characterized by “quantitative convergence but qualitative divergence.” Specifically, learners attenuate subject–predicate boundaries while reinforcing verb–object boundaries, resulting in an inverted prosodic hierarchy that prioritizes utterance fluency at the expense of structural fidelity. These results advance our understanding of the mechanisms underlying L2 prosodic acquisition.

Technology Category

• Natural Language Processing: Lexical Semantics and Morphology
• Constraint Satisfaction and Optimization: Constraint Learning and Acquisition
• Cognitive Modeling & Cognitive Systems: Affective Computing

Application Category

• Search and Retrieval-Augmented AI: Multilingual and cross-lingual Web search
• Web Mining and Content Analysis: Mining multimedia, multimodal, multilingual, cross-lingual Web data
• Semantics and Knowledge: Methods to enhance, augment, integrate or synergize semantic models such as knowledge graphs and LLMs

Abstract

While second language (L2) learners may acquire target syntactic word order, mapping this syntax onto appropriate prosodic structures remains a persistent challenge. This study investigates the fossilization and stability of the L2 syntax-prosody interface by comparing 67 native Mandarin speakers with 67 Vietnamese learners using the BLCU-SAIT corpus. By integrating C-ToBI boundary annotation with Dependency Grammar analysis, we examined both the quantity of prosodic boundaries and their mapping to syntactic relations. Results reveal a non-linear acquisition: although high-proficiency learners (VNH) converge to the native baseline in boundary quantity at the Major Phrase level (B3), their structural mapping significantly diverges. Specifically, VNH demote the prosodic boundary at the Subject-Verb (SBV) interface (Major Phrase B3 -> Prosodic Word B1), while erroneously promoting the boundary at the Verb-Object (VOB) interface (Prosodic Word B1 -> Major Phrase B3). This strategy allows learners to maintain high long phrasal output at the expense of structural accuracy. This results in a distorted prosodic hierarchy where the native pattern is inverted.

Problem

• L2 prosody
• syntax-prosody interface
• fossilization
• Mandarin
• prosodic hierarchy

Innovation

• prosody-syntax interface
• C-ToBI annotation
• Dependency Grammar
• L2 Mandarin
• prosodic boundary mapping