TONAL COARTICULATION IN THAI

In tones, coarticulatory effects occur in much the same way as they do between consonants and vowels. Earlier studies on tonal coarticulation leave open the question as to whether the primary direction of coarticulatory effects is the same across tone languages, and whether the effect involves primarily a change in tone height or a change in slope as well. The present study investigated the magnitude and extent of tonal coarticulation in Thai. Ten speakers produced all 25 possible sequences of two tones from the five tones of Thai embedded in a carrier sentence. Tonal contours were analyzed in terms of height and slope of the fundamental frequency. Results from statistical analysis indicated that the coarticulatory effects were not symmetric. Thai tones were more influenced by carry-over than by anticipatory coarticulation. Carry-over coarticulation affected a greater number of Thai tones and extended farther into adjacent tones. Coarticulation affected primarily height; slope was relatively unaffected. Magnitude of the effects was fairly uniform regardless of direction of coarticulation.