Acoustic Phonetics of Lao Tones
Marlys A. Macken, Ph.D.
Professor – Department of Linguistics
University of Wisconsin-Madison
The tones of Tai languages are typically studied within the historical model and method of Gedney (1964), using a basic twenty word word-list for twenty categories that vary by initial consonant, and Proto-Tai tones (*A,*B, and *C) and syllable type (smooth versus checked syllable). Synchronic descriptions of Lao tones posit five or six main tones (in smooth syllables) with considerable differences by dialect and in the nature of each tonal phoneme (e.g. rising, falling, low, high, etc.). This paper presents acoustic phonetic data for the Lao tones in two Lao dialects, the Central Vientiane dialect and the Southern dialect as spoken in Savannakhet. Data include multiple tokens of at least five words per Gedney category, words spoken in both isolation and in sentence frame, and native speaker judgments about phonemic contrast and where tones in particular words are the same or different. Results include (i) cross-dialect similarities in the phonological factoring of the Gedney 20 category proto system; (ii) differences between dialect in number of the tone phonemes (five tone phonemes in the Central dialect (as per Crisfield and Hartmann 2002, Enfield 2000, and Brown 1965, among others), five tone phonemes in the Savannakhet Southern dialect that are different from the five tone phonemes in Vientianne and different from the six tone phonemes for the Southern dialect as spoken further south of Savannakhet in Pakse (a not surprising variation given other reports); (iii) differences in the phonological shape of the tone phonemes; and (iv) within category acoustic differences that provide dramatic evidence of the underlying historical development and the synchronic dialect system from Northern to Southern Laos.