Perceptual Metathesis in Tsou: A Reanalysis of Segment Transposition in Voice Paradigms

In Tsou, a group of verb stems displays a peculiar ordering contrast in which a vowel + consonant sequence in actor voice is transposed in the corresponding nonactor voice , as seen in the contrast of t<m>eʔsi ‘sew, actor voice ’ vs. tʔes-a ‘sew, patient voice ’ and tʔes-neni ‘sew, referential voice ’. This study argues that Tsou segment transposition can be viewed as an instance of perceptual metathesis, in which the long-durational cues of an underlying postvocalic consonant extend and affect the realization of the adjacent vowel, resulting in a reinterpretation of the acoustic effects as being caused by a prevocalic consonant. Through an exploration of the phonetic characteristics of the sounds involved and the context in which they appear, this study presents a unified treatment of three puzzling aspects of Tsou segment transposition: (i) transposing consonants are limited to laryngeals and palatal glides; (ii) the direction of the change appears ambiguous (VC > CV or CV > VC) due to the undetermined status of the underlying order; and (iii) the VC ~ CV alternation is confined to specific voice categories, which raises questions about whether the nature of the change is purely phonologically defined, or requires reference to specific morphosyntactic categories.