Co-articulation between consonant and vowel in Taiwanese bisyllables

This study investigates the C-V and V-C co-articulations in the Taiwanese bisyllabic words that contain the sequences of [V.CV] and [VC.V], where C = [p t k] and V = [i a u]. It determines the degree of C-V and V-C co-articulations in four segment sequential contexts, the tautosyllabic [.CV] and [VC.] and the heterosyllabic [C.V] and [V.C] in Taiwanese, as reflected in the extent of change in tongue position during the vowels [i a u] preceded or followed by the consonants [p t k]. Using NDI Wave, tongue positions during the test bisyllabic words were recorded of five male young adult Taiwanese speakers. The data on the change in tongue position reveal that the degree of co-articulation decreases (i) when C = [t] > C = [k] > C = [p] and (ii) when V = [a] > V = [u] > V = [i]. The degree of the co-articulation between consonant and vowel tends to be larger in the [VC.] sequences than in the [.CV] sequences. As for the two heterosyllabic [C.V] and [V.C] sequences, the syllable boundary impedes the co-articulation between the consonant and vowel in [C.V], but not in [V.C]. The data agree with the fact that in Taiwanese the coda consonant in the [C.V] sequence does not undergo re-syllabification across the syllable boundary, while the onset consonant in the [V.C] sequence also functions as the coda of the preceding syllable crossing the syllable boundary. Overall, the degree of C-V and V-C co-articulations varies with the consonant type, vowel type, segment position in the syllable, and presence/absence of the syllable boundary in the sequences.