Tone production, tone perception and Kammu tonogenesis

The Northern and Western dialects of the Mon-Khmer language Kammu use fundamental frequency to distinguish words, while the Eastern dialect relies on the contrastive voicing of initial consonants to distinguish words which display an F0 contrast in the other dialects. The production and perception of tones in the three dialects is investigated, using recordings and perception tests. As expected, Northern and Western Kammu speakers do use F0 to distinguish words, as seen both in their production and in perception tests, which show that they could distinguish small F0 differences. In contrast, Eastern Kammu speakers neither produce nor perceive F0 differences at the lexical level. Furthermore, the voiceless and voiced stops in Eastern Kammu cause smaller F0 perturbations in the following vowel than might be expected for a language undergoing tonogenesis. The significance of these results for tonogenesis is discussed, as well as their relevance for the notion of ‘tone language’.