Phonetic detail encoding in explaining boundary-modulated coarticulation

Abstract

This study examines the acoustic outputs in boundary coarticulation and attempts to explain the native and nonnative production differences in relation to speech planning. English consonant clusters across words produced by English (L1) and Mandarin (L2) speakers are analyzed. This study focuses on two segmental features (place of articulation and voicing) and computes three acoustic-based measurements (internal release, closure durations and closure shortening). The results find a lesser coarticulation degree in L2 production, and differing acoustic deviations varying with speakers’ proficiency level. The results also suggest that cross-word planning involving place of articulation is robust in both L1 and L2 production, while cross-word voicing encoding is not available in L2 speech. The asymmetry in L2 encoding is compatible with a competitive gestural selection analysis, and the implications of L1 production have been interpreted as in favor of a richer mental representation and finer-level execution than the syllable-sized programming. The preliminary results support the core assumption that L1 and L2 coarticulation differences arise from phonological and phonetic encoding. This study adds cross-linguistic output-based evidence on speech planning and encourages speech models to further specify the very late stage of phonetic encoding.