The typologically rare approximant inventory of Kajkwakhrattxi: A series of natural sound changes

Abstract

Kajkwakhrattxi, a Northern Jê language spoken by fewer than 30 elders in Mato Grosso, Brazil, exhibits a typologically rare sound inventory, especially with respect to its series of approximants: /w, w̃, ʍ, ɽ, ɽ̃, j/, realized as a total of 17 different surface allophones: [w, w̃͡w, w̃, ʍ, ɥ, ɥ̃͡ɥ, ɥ̃, ɥ̊, ɾ, ɾ̃, ɽ, ɽ̃, ɻ, ɻ̃, ɻ̊, j, j̃]. We propose a novel reconstruction of Proto-Northern-Jê that accounts for this unusually dense inventory of approximants, namely as the result of a series of natural sound changes involving processes of lenition and assimilation. Our analysis makes use of novel fieldwork data on three underdocumented and endangered languages of the family: Kajkwakhrattxi, Panãra, and Kayapô. As a result, our reconstruction is based on a more phonetically detailed and internally coherent data set than was available to previous comparative work on Jê languages. Our results provide evidence for the possible breadth of diversity in the phonological systems of natural languages, both synchronically and diachronically, and advances our knowledge of the sound changes that occurred from Proto-Northern-Jê to its daughter languages.