“Brightness”, “Darkness” and the dimensionality of vowel perception

Abstract

The frequent use of only two labels in impressionistic descriptions of vowel quality, from antiquity up until the present day, suggests the possibility of perceptually ordering vowel sounds along a single dimension corresponding to a single auditory attribute. Results of experiments in “phoneme grouping” and in machine perception also seem not unfavourable to such a hypothesis. Perception tests were carried out to investigate the reality of the “dark/bright” continuum for naive listeners and the relationship of this auditory dimension to acoustic factors. Preliminary results indicate a correspondence between “brightness” and the degree of separation of first and second formant. Further tests with extended stimulus sets are necessary to confirm this.