Tets´ǫt'ıné prefix vowel length: Evidence for systematic underspecification.

Tetst'ıné is a dialect of Dëne Sųłıné (ISO: CHP) spoken in Canada's Northwest Territories. The verb system of Tetst'ıné has only recently been described (Jaker and Cardinal 2020); this paper is the first to propose an analysis of the distribution of long and short vowels in Tetst'ıné prefixes. In Tetst'ıné, all long vowels in prefixes are derived from intervocalic consonant deletion, although not all cases of intervocalic consonant deletion result in a long vowel. Whether or not deletion of an intervocalic consonant results in a long or short vowel depends on a combination of two factors: the consonant that was deleted, and the morphological level to which the preceding prefix belongs. In this paper, I propose that the basic generalization about prefix vowel length can be stated in terms of Systematic Underspecification (Kiparsky 1993). I claim that prefix vowels, unlike stem vowels, have zero moras underlyingly, and only acquire a mora after passing through at least one level of the phonology. This analysis predicts that prefix vowel length ought to be subject to a Derived Environment Effect (DEE), for which there is indeed evidence. The pattern of mora insertion in Tetst'ıné prefix vowels is thus an example of the interleaving of phonology and morphology, and illustrates how phonological behaviour can be to some extent predicted based on morphological structure.