Biomechanical adaptation mechanisms of temporomandibular joint movement in English pronunciation learning

The temporomandibular joint (TMJ) plays a critical role in speech articulation, yet its biomechanical adaptation during second-language pronunciation learning remains underexplored. Non-native English speakers often exhibit excessive jaw movements and inefficient neuromuscular activation, which can impede phonetic accuracy and speech fluency. Despite advancements in phonetic training, existing methodologies lack an integrated biomechanical approach that quantitatively assesses TMJ adaptation. This study investigates the biomechanical adaptation mechanisms of TMJ movement in English pronunciation learning, focusing on jaw kinematics, neuromuscular adaptation, and phonetic precision. The research aims to quantify TMJ adaptation and its influence on speech efficiency, providing an evidence-based framework for pronunciation training. A four-week structured pronunciation training program was conducted with 72 non-native English speakers. Three biomechanical techniques were employed: Motion Capture Analysis (MCA) for jaw kinematics, Electromyography (EMG) for neuromuscular activity, and Acoustic-Phonetic Analysis for pronunciation accuracy. Additionally, Structural Equation Modeling (SEM) was applied to evaluate causal relationships between TMJ biomechanics and phonetic precision. Findings demonstrated a 39.6% reduction in jaw displacement variability, a 33.3% decrease in masseter activation, and a 35.3% improvement in syllable timing variability. While kinematic and neuromuscular adaptations correlated with enhanced phonetic precision, SEM results suggested additional mediating factors in pronunciation learning. This study provides quantitative evidence that structured pronunciation training improves TMJ biomechanics, neuromuscular efficiency, and phonetic accuracy. The findings have implications for speech training, AI-assisted pronunciation tools, and clinical speech therapy. Future research should explore long-term TMJ adaptation, tongue biomechanics, and cross-linguistic differences in speech motor learning.