LINGUIST List 14.2634

Tue Sep 30 2003

Diss: Phonetics: Ghavami: 'The Effects of...'

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  1. gmodarresi, The Effects of Syllable Boundary

Message 1: The Effects of Syllable Boundary

Date: Mon, 29 Sep 2003 16:31:57 +0000
From: gmodarresi <gmodarresiyahoo.com>
Subject: The Effects of Syllable Boundary

Institution: University of Texas at Austin
Program: Department of Linguistics
Dissertation Status: Completed
Degree Date: 2002

Author: Golnaz Modarresi Ghavami 

Dissertation Title: The Effects of Syllable Boundary, Stop Consonant
Closure Duration, and VOT on VCV Coarticulation

Linguistic Field: Phonetics 

Dissertation Director 1: Harvey M Sussman

Dissertation Abstract: 

This study investigated whether the vocalic gestures in VCV sequences
are produced with a single diphthongal movement as predicted by the
superimposition model of coarticulation or as separate events as
predicted by a phoneme-by-phoneme view. 'Troughs' or discontinuities in
anticipatory vowel-to-vowel coarticulation during the closure period
of bilabial stops in symmetrical VCV sequences have provided evidence
in favor of a phoneme-by-phoneme view. This investigation sought to
uncover the acoustic correlates of troughs in VCV utterances produced
by five English and two Persian speakers.

Acoustic evidence for troughs was found in frequency changes of F2
transitions in symmetrical [V.bV] and [V.phV]sequences. F2 transitions
indicative of tongue-related trough effects were influenced by the
syllabic affiliation of the intervocalic stop and to a lesser degree
by its voicing properties. Changes in consonantal closure duration did
not elicit troughs.

Locus equations (LE) were employed as a second methodology to uncover
the acoustic correlates of troughs in a variety of consonantal and
vocalic contexts. LE slopes capture CV coarticulation. Troughs would
be expected to lower slope values. Consistently lower LE slopes at the
CV2 interface were observed with closed versus open and voiceless
versus voiced stops. LE slopes remained stable across changes in
consonantal closure duration.

Bidirectional V-to-V coarticulatory effects were also explored. The
superimposition model predicts no changes in V-to-V coarticulation as
a function of the syllabic affiliation, closure duration, and the
voicing properties of an intervocalic stop. Results showed reduced
anticipatory V-to-V effects in closed versus open, geminate versus
singleton, and voiceless versus voiced conditions in English and with
lesser degrees of consistency in Persian. Increased carry-over V-to-V
effects were observed in closed versus open syllables in English and
in voiceless versus voiced conditions in Persian. Carry-over effects
were generally smaller in geminate versus singleton utterances in
English and Persian and across voiceless versus voiced stops in
English.

The results of this study support a phoneme-by-phoneme view of
segmental organization in which vocalic and consonantal gestures are
distinct but temporally and spatially overlapping events and affect
one another in varying degrees based on the degree of their overlap.
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