Diphthongs in Tohono O'odham

This article examines the distribution of diphthongs in Tohono O'odham (Uto-Aztecan), dividing them into two types, light and heavy, on the basis of three characteristics: stress placement (a light diphthong occurs in either stressed or unstressed syllables while a heavy diphthong occurs in only stressed positions); reduplicative processes (a light diphthong undergoes segment-retention reduplication, and a heavy diphthong, segment-skipping reduplication); and restrictions on the phonemes allowed by each type (light diphthongs can contain [i], whereas heavy diphthongs do not). This analysis has implications for the treatment of Tohono O'odham diphthongs in terms of mora theory, for the status of the high front vowel, and for pedagogy.