Just How Contrastive Is Word-Initial Consonant Length? Exploring the Itunyoso Triqui Spontaneous Speech Corpus

Itunyoso Triqui (Otomanguean: Mexico) has a typologically uncommon contrast between singleton and geminate consonants which occurs only in word-initial position of monosyllabic words. In this paper, we examine how functional factors contribute to the observed phonetic variation in production for this marked contrast. Geminate and singleton onsets are not equally distributed in the language—singleton onsets greatly outnumber geminate onsets. Moreover, the distribution of geminate and singleton onsets varies by manner of articulation and consonant onset. Functional factors also vary across the contrast space. In our first study, we focus on durational data from a smaller, 2-hr corpus and test the degree to which functional factors (Shannon entropy, functional status, lexical competitor size, and segment frequency) influence the production of the contrast. With the exception of entropy, we find that several of these factors play a role in predicting the robustness/hyperarticulation of the contrast realization. Content words with onset singleton obstruents are more likely to be lengthened than content words with onset singleton sonorants. Segments with a larger token frequency from a larger, 90K word corpus are more likely to be hyperarticulated. In our second study, we examine how the observed durational factors lead to differential patterns of consonant undershoot by examining patterns of lenition. Combined, our findings demonstrate how functional factors influence language variation and may lead toward particular diachronic trajectories in the evolution of rare sound contrasts like these in human language.