Classification of stop consonant place of articulation

Abstract

In this study we develop an experimental procedure for examining the relative importance of knowledge-based cues for identifying place of articulation for stop consonants. A set of acoustic attributes is selected for place classification of stops: amplitude and energy of burst, formant movement of adjacent vowels, spectrum of noise after the release, and some temporal cues. The ability of each attribute to separate the three places is evaluated by the classification error based on the distributions of its values for the three places, and another quantifier based on F ratio. These two quantifiers generally agree and show how well each individual attribute separates the three places. Linear discriminant function analysis is used to address the relative importance of these attributes when combinations are used. Their discriminating abilities and the ranking of their relative importance to the classification in different vowel and voicing contexts are reported. The overall findings are that attributes relating to the burst spectrum in relation to the vowel contribute most effectively, while formant transition is somewhat less effective. The approach used in this study can be applied to different classes of sound, as well as stops in different noise environments. [Work supported by NIH Grant Number DC 02978.]