Relating formant variability to vowel constriction features extracted from pellet positions.

Abstract

Quantal theory claims that sounds which are common in phoneme inventories, such as [i] and [a], are articulated in vocal tract regions where acoustic patterns are relatively insensitive to variation in constriction location. Perkell and Nelson [J. Acoust. Soc. Am. 77, 1889–1895 (1985)] tested this claim using a principal components analysis of x-ray microbeam data. As predicted, tongue pellets showed most positional variation in an axis parallel to the hard palate in [i] and to the pharynx wall in [a]. An earlier replicative study using [i], [a], and three other vowels [Ahalt etal., J. Acoust. Soc. Am. 89, 1871 (1991)] showed that pellet data are more easily interpreted in terms of relative variation in constriction location and degree if they are transformed nonlinearly into a coordinate space where x and y values express location along and distance from the opposing wall of the vocal tract. The present study examined the relationship between formant values and pellet positions in this transformed space, and found some support for quantal theory. In particular, all good correlations involved positional variation in the y dimension for pellets near the constriction. [Work supported by the NSF.]