An historical argument against tone features

Starting from the observation that in segmental phonemes sound changes target classes of features, rather than phonemes, but that tone changes tend to affect each tone as an individual unit rather than series of tones, we argue that tones should not be analysed into combinations of features. Examples are drawn from the litterature on the evolution of Asian tone systems, and from a case study by the author from a group of Tibeto-Burman languages of Nepal. We postulate that tonal systems which are amenable to a feature analysis are a special case, corresponding to an intermediate stage in the formation or evolution of tone systems, when tonogenesis linked to a consonantal mutation is still in process