Tone space and universals of tone systems
Jean-Marie Hombert · The Journal of the Acoustical Society of America · 1977
The purpose of this paper is to present a mathematical model which predicts the most likely tone shapes of a tone system. Given the total number of lexical tones the model will output two numbers for each tone. The first number represents the onset and the second number the offset of the tone on a five-point scale. This model is based on the principle of maximal perceptual distance and minimal articulatory difficulty. The parameters measuring perceptual distance and articulatory difficulties were obtained from consideration of previously reported data by other researchers and two recent experiments, The effect of using various measurements of perceptual distance (euclidian, city block, etc.) and various relative weights for articulatory vs auditory factors is also investigated. The predictions made by the model were satisfactorily matched with actual data from more than one hundred tone languages. The notion of “most likely tone shapes” based on a trade off between maximum perceptual distance and minimum articulatory difficulty is very useful for understanding why and how tone systems evolve. [Work supported by NSF.]