Vowel acoustics reliably differentiate three coronal stops of Wubuy across prosodic contexts

The present study investigates the acoustic differentiation of three coronal stops in the indigenous Australian language Wubuy. We test independent claims that only VC (vowel-into-consonant) transitions provide robust acoustic cues for retroflex as compared to alveolar and dental coronal stops, with no differentiating cues among these three coronal stops evident in CV (consonant-into-vowel) transitions. The four-way stop distinction /t, t̪ , ʈ, c/ in Wubuy is contrastive word-initially (Heath 1984) and by implication utterance-initially, i.e., in CV-only contexts, which suggests that acoustic differentiation should be expected to occur in the CV transitions of this language, including in initial positions. Therefore, we examined both VC and CV formant transition information in the three target coronal stops across VCV (word-internal), V#CV (word-initial but utterance-medial) and ##CV (word- and utterance-initial), for /a / vowel contexts, which provide the optimal environment for investigating formant transitions. Results confirm that these coronal contrasts are maintained in the CVs in this vowel context, and in all three positions. The patterns of acoustic differences across the three syllable contexts also provide some support for a systematic role of prosodic boundaries in influencing the degree of coronal stop differentiation evident in the vowel formant transitions.