Pitch and voice quality in Burmese vowels

Abstract

Burmese vowels are pronounced with a four-way contrast in laryngeal configuration, described as high, low, creaky, and killed registers [Bradley, Tonation, Pacific Linguistics Series A-62 117–132 (1982)]. However, acoustic descriptions differ as to whether the registers should be defined in terms of pitch or voice quality [Watkins SOAS Working Papers in Linguistics: 10, 139–149 (2000)]. This study investigates whether voice quality or pitch is the more consistent carrier of contrast across the four registers. Four speakers pronounced 20 words (5 vowels ×4 registers) inside a frame sentence surrounded by syllables of low register. Each sentence was repeated five times consecutively. For each syllable, F0 measures were taken at each quartile, as well as peaks and valleys. Voice quality was quantified in terms of spectral slope [Gordon and Ladefoged, J. Phonetics 29, 383–406 (2001)], specifically the difference in dB between the first and second harmonics in an FFT spectrum over a 50-ms window. Results indicate that pitch more reliably indicates register than voice quality. While there was no significant difference in spectral slope between registers, the four registers differed consistently in height and timing of pitch peaks.