Vowel-Rhotic Metathesis in Guarayu

Abstract

Guarayu (Tupi-Guarani, Bolivia) has undergone a diachronic process of metathesis in which a word-final tap /ɾ/ exchanged positions with a preceding high nonfront vowel /ɨ/ or /u/. We propose a scenario for how such an exchange could occur, using Guarayu as a case study. A tap/vowel metathesis is presented as a timing readjustment that led to an exchange of phonemic status between a phonemic vowel on one side of the tap and an automatic intrusive vowel on the other. We suggest that, in Guarayu, this realignment may have been facilitated by an insufficiency of phonetic cues that a listener might routinely use to accurately perceive and locate the transition between the vowel and tap involved in the exchange. We propose that phonological factors also played a role and that metathesis was perception optimizing, and we report the results of a speech perception experiment that supports this interpretation. Connections are drawn between the Guarayu metathesis and patterns of vowel epenthesis and deletion known t...