A comparison between the change of vowel systems and the acoustic characteristics of vowels in Thai Mon and Burmese Mon: a tendency towards different language types
Abstract:
This research aims to analyze the vowel systems and acoustic characteristics of vowels in four Thai Mon varieties: Ban Kho (TM1), Ban Muang (TM2), Ban Bangkhanmak (TM3) and Ban Nong Duu (TM4) and four Burmese Mon varieties: Mokaneang (BM1), Tancanuʔ (BM2), Səpuʔ (BM3) and Kawbein (BM4), in order to prove that Thai Mon and Burmese Mon have different vowel systems and acoustic characteristics of vowels and have a tendency towards different language types. In order to analyze the vowel systems, 500 basic vocabulary items, 300 words from Shorto (1962) and Diffloth (1984) and 112 words from Bauers unpublished Mon dialect checklist, were used to interview one informant from each variety. For acoustic analysis, three informants from each variety were asked to pronounce 100-109 words 3 times. The total number of test tokens was 7,515. The relative amplitude of H1-H2, H1-H3, H2-H4, H1-A1, H1-A2, H1-A3, duration, fundamental frequency and formant frequency of vowels of all tokens were analyzed with Praat version 5.2.27 and were statistically tested with t-test (0.05 level of significance). The results, which confirm some hypotheses, are as follows: Thai Mon vowel systems differ from those of Burmese Mon; confirming the hypothesis, but the vowel systems among 4 Thai Mon varieties and 4 Burmese Mon varieties are different, disproving the hypothesis. The relative amplitude (notably H1-A1) significantly differentiates clear vowels from breathy vowels in both Thai Mon and Burmese Mon varieties in accordance with the hypothesis. However, duration is not the cue to distinguish these vowels; rejecting the hypothesis. The fundamental frequency of vowels discriminates clear and breathy vowels in both Thai Mon and Burmese Mon varieties which initially were hypothesized only for Thai Mon. In addition, the study has not found that formant frequencies of clear vowels differ from those of breathy vowels in Thai Mon and Burmese Mon varieties, which does not confirm the hypothesis. The study reveals that both H1-A1 and the fundamental frequency of vowels differentiate clear vowels from breathy vowels in Thai Mon and Burmese Mon varieties, showing that phonation type and pitch are the prominent components of Thai Mon and Burmese Mon varieties, in other words they are register languages with obvious pitch patterns. According to the results of the acoustic study, if the language change does occur, Thai Mon and Burmese Mon varieties could become tonal languages in the future. However, on-gliding and off gliding occur to most vowels in Burmese Mon varieties. This could indicate that there might be more diphthongs in Burmese Mon varieties in the future but not in Thai Mon varieties. This phenomenon may be indicative of the different routes of change in Thai Mon and Burmese Mon, i.e. Thai Mon varieties may become solely tonal languages while it is plausible that Burmese Mon varieties may in the future become either tonal or restructured languages with complicated vowel systems.