While EPG registers the location and amount of
tongue-palate contact, ultrasound can capture most
of the tongue contour. Previous studies have not
systematically quantified lingual coarticulation
using EPG and ultrasound simultaneously. This
study used both techniques for analysing vowel-consonant
coarticulatory effects.
Four speakers of Scottish English produced /VC/
sequences with the consonants /p, f, t, s, l, r, k/ and
the vowels /a, i/. The difference between each
consonant in the two vowel contexts was computed
using an EPG measure and an ultrasound measure.
Additionally, temporal coarticulation was analysed,
using EPG data.
A significant positive correlation was observed
between the two measures, with labial consonants,
followed by /r/, having the highest values. The two
techniques also provided complementary data on
lingual coarticulation. The velar stop was more
coarticulated on the EPG measure than on the
ultrasound measure, because EPG registered a shift
in closure location across vowel contexts, while
ultrasound captured the close proximity of the
tongue root across the vowel contexts. The sibilant
was more coarticulated on the ultrasound measure
than on the EPG measure, because ultrasound,
unlike EPG, registered vowel-dependent difference
in the tongue root. Combined EPG and ultrasound
data would be useful in future studies of
coarticulation.casl[1]. P. Bacsfalvi, B.M. Bernhardt, & B. Gick.
Electropalatography and ultrasound in vowel remediation
for adolescents with hearing impairment. Advances in
Speech-Language Pathology, 9, 36-45, 2007.
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[7]. J. Scobbie, S. Wood, & A. Wrench. Advances in
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Clinical Linguistics and Phonetics, 18, 373-389, 2004.
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ultrasound images. Clinical Linguistics and Phonetics,
19, 455-502, 2005.
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[12]. Y. Vazquez Alvarez and N. Hewlett. The trough
effect: an ultrasound study. Phonetica, 65:105-121, 2007.
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velar-vowel coarticulation. Journal of the Acoustical
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ultrasound. QMU Speech Science Research Centre
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