Cue weight in the perception of Trique glottal consonants

This paper examines the perceptual weight of cues to the coda glottal consonant contrast in Trique (Oto-Manguean) with native listeners. The language contrasts words with no coda (/Vː/) from words with a coda glottal stop (/VɁ/) or breathy coda (/Vɦ/). The results from a speeded AX (same-different) lexical discrimination task show high accuracy in lexical identification for the /Vː/-/Vɦ/ contrast, but lower accuracy for the other contrasts. The second experiment consists of a labeling task where the three acoustic dimensions that distinguished the glottal consonant codas in production [duration, the amplitude difference between the first two harmonics (H1-H2), and F0] were modified orthogonally using step-wise resynthesis. This task determines the relative weight of each dimension in phonological categorization. The results show that duration was the strongest cue. Listeners were only sensitive to changes in H1-H2 for the /Vː/-/Vɦ/ and /Vː/-/VɁ/ contrasts when duration was ambiguous. Listeners were only sensitive to changes in F0 for the /Vː/-/Vɦ/ contrast when both duration and H1-H2 were ambiguous. The perceptual cue weighting for each contrast closely matches existing production data [DiCanio (2012 a). J. Phon. 40, 162-176] Cue weight differences in speech perception are explained by differences in step-interval size and the notion of adaptive plasticity [Francis et al. (2008). J. Acoust. Soc. Am. 124, 1234-1251; Holt and Lotto (2006). J. Acoust. Soc. Am. 119, 3059-3071].