Coarticulation as synchronised CV co-onset – Parallel evidence from articulation and acoustics

This study tested the hypothesis that consonant and vowel are synchronised at the syllable onset, and that such synchronised co-onset is the essence of coarticulation. Articulatory data were collected for Mandarin Chinese, using Electromagnetic Articulography (EMA), and acoustic data were collected simultaneously. As a departure from conventional approaches, a minimal triplet paradigm was applied, in which divergence points between movement trajectories in contrastive pairs were used to determine segmental onsets. Triplets of disyllabic words consisting of two matching contrastive pairs in a C ₁ V ₁ null ₂ V ₂ structure were used, whereby the consonant pair differed only in C ₂ and the vowel pair differed only in V ₂ (the numerical indices indicate syllable position). Both articulatory and acoustical results showed that the articulation of vowels and consonants started at about the same time, thus supporting the CV synchrony hypothesis. The realisation of CV synchronisation was dimension specific, however. For any particular articulator, only the dimensions free of consonantal requirement started their movements toward the vowel from the syllable onset, while the rest of the dimensions moved toward successive consonantal and vocalic targets. The finding of CV co-onset increases the amount of temporal overlap between C and V relative to the widely assumed CV asynchrony. The evidence of dimension-specific sequential articulation sheds further light on coarticulation by offering a timing-based explanation for the well-known phenomenon of coarticulation resistance.