Movement duration and movement stiffness in long and short consonants

Abstract

This study examined the relationship between movement duration and movement stiffness in speech. Stiffness was measured as the interval from movement onset to peak velocity. The speech material consisted of long and short Japanese consonants produced by native speakers. A magnetometer was used to track articulatory movements. For the lower lip, the velocity of vertical closing movement for bilabial consonants was measured, while the speed of the tongue tip was measured for dental stops and fricatives. Results from six subjects show that the lower lip movement duration was longer for the long consonants, which also had a lower stiffness than their short cognates. The results also show higher correlations between duration and stiffness for the short consonants. The results for the tongue tip showed more variability across and within subjects, although the overall trend was similar to the one found for the lower lip. In addition, all correlations between tongue tip movement duration and stiffness were high. These results extend earlier work on the same relationship, where it has mostly been studied across variations in speaking rate. They also suggest potential differences between articulators and between stops and fricatives. [Work supported by NIH.]