ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06
5pSC2. Prediction of obstruent spectra from the slope of preceding and
following second formant transitions.
Gary Weismer
Vidya Guhan
Ray D. Kent
Dept. Commun. Disord. and Waisman Ctr., Univ. of Wisconsin-Madison, 1500
Highland Ave., Madison, WI 53705-2280
There is evidence that the slope of second formant (F2) transitions
provides an index of the severity of speech mechanism involvement in motor
speech disorders [Weismer et al., 1085--1098 (1992)]. From an
articulatory perspective, the slope of the F2 transition is an ordinal index of
the rate of change in vocal tract configuration. It was hypothesized that, for
single words, these F2 slopes would predict quantitative spectral
characteristics of adjacent obstruents, under the assumption that the rate of
change in vocal tract configuration during a vocalic segment would influence
the articulation of a preceding or following obstruent. Quantification of
obstruent spectra was achieved by means of spectral moments, which were
regressed on F2 transition slopes for a group of normally articulating men and
a group with amyotrophic lateral sclerosis, a degenerative motoneuron disease
typically associated with dysarthria. Results partially confirmed the
hypothesis for both groups of subjects; the findings will be discussed in terms
of separate treatment of vocalic and obstruent segments in a model of speech
intelligibility. [Work supported by NIH.]