ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06
1aSC14. On the ``locus equation'' and its relation with the consonant
place of articulation.
Sig. Dept. ENST, 46 Rue Barrault, 75634 Paris, France
Univ. of Stockholm, S-10691 Stockholm, Sweden
The specification of the consonant place of articulation from the locus
equation coefficients [Sussman et al., 1256--1268 (1991)] is subject
to discussion. For instance, Fowler [Percept. Psychophys. 55, 597--610 (1994)]
claims that these coefficients can vary significantly within homorganic
consonants. In order to study the relation between these coefficients and place
of articulation, V1CV2 utterances were stimulated using the distinctive region
model and three different instants of initiating the second vowel: before the
acoustic segment of the consonant, at the beginning of that segment, and, in
the third case, after it. The results show that linear locus equations can be
acceptably fitted to those conditions, but that their coefficients vary as a
function of the second vowel onset. It was noted that the locus equations are
sensitive to degree of consonant--vowel coarticulation. Also, when y intercepts
were plotted against the associated slopes for a given place and across the
simulated timing conditions, highly linear relationships were observed. Thus
the coefficients of such ``second-order'' locus equations stay constant for a
given place despite variations in temporal and coarticulatory conditions.
Hence, for natural speech, such ``second-order'' parameters might be a more
stable place correlate than first-order coefficients.