Owen, R. Wyn2012-07-032012-07-031836-6821ISO 639-3 Language codes: shn, kkhhttp://hdl.handle.net/1885/9117This paper presents an analysis of the tones of five contemporary Tai Khuen varieties in order to investigate the differences in the number of distinctive tones reported in the literature. The present study shows that while some contemporary speakers have a tone system with six tones, most speakers have only five tones. Comparison of the distribution and phonetic characteristics of the tones in the contemporary varieties with previous studies shows that the five tone system was derived by the coalescence of two tones in the six-tone system. Investigating the factors that determine which tone system a particular contemporary speaker uses leads to the conclusion that language contact with five-tone Shan was the cause of the changeAustralian National University20 pages"Copyright vested in the author; released under Creative Commons Attribution Licence" - at head of journal articlephoneticstoneslanguage contact2012-07-01