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An ultrasound study of the trough effect in VhV sequences
Natalia Zharkova
Queen Margaret University College,
Speech and Hearing Sciences
nzharkova@qmuc.ac.uk
Ultrafest III, Arizona 16 April 2005
/h/ /h/ is unspecified for tongue position (e.g. Keating
1988, Pierrehumbert & Talkin 1992, Ladefoged 2001, Karbownicki 2004)
/h/ is also unspecified for lip and jaw position…
/h/ has a lot of freedom for coarticulation
Troughs A “trough”, or a lowering of the tongue, has
been found in bilabial consonants surrounded by identical vowels (e.g. Houde 1967, Gay 1974, Gay & Ushijima 1974, Bell-Berti & Harris 1974, Engstrand 1988, Svirsky et al. 1997, Lindblom et al. 2002, Fuchs et al. 2004, Vazquez Alvarez, Hewlett & Zharkova 2004)
Bilabial consonants, like /h/, are considered unspecified for a particular tongue position
So:
interesting to see what happens when /h/, which is even more unspecified than bilabials, is between two identical vowels
Questions: What would be the pattern of tongue
behaviour during VhVs? Specifically: Does the tongue maintain the same position
throughout the VhV sequence? If not – what differences occur? E.g. is there a trough on /h/? Is the V1
position different from the V2 position?
Data collection QMUC ultrasound system three native British English speakers data = /ihi/, /uhu/, /aha/ carrier phrase “I said … too”
(“eehee”, “oohoo”, “aha”) sixteen times each
Distances along vertical measure bar:
V1 – C C – V2
V1
V2
/h/
2. Measuring tongue movements throughout VhVs
extracting xy spline coordinates from US analysis software
importing xy values into Matlab
3. Comparing whole contour shapes
Black solid line –V1
Red solid line –/h/
Blue dashed line – V2
Typical tongue shape pattern during /uhu/
Calculating the distance from each point on the C curve to its nearest neighbour on the V1 curve and separately on the V2 curve
Plotting these distances
Distances between V1, C and V2 curves
Distances between V1, C and V2 curves
Black solid line –V1 Red solid line – /h/
Blue dashed line – V2
Results
1. Comparing occurrence of different tongue shape patterns
Trough (highest point of C below both VV) Antitrough (highest point of C above both VV) Neutral (highest point of C between two VV)
Tongue shape patterns distribution by vowel
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
i u a
Trough
Neutral
Antitrough
Distances of tongue movement
Very small
distances
!!!!!!!!!!!!
aha ihi
uhu
Error Bars show Mean +/- 1,0 SD
Bars show Means
-1,0
-0,5
0,0
0,5
1,0
dis
tan
ce
, mm
first second
-1,0
-0,5
0,0
0,5
1,0
dis
tan
ce
, mm
aha ihi
uhu
Error Bars show Mean +/- 1,0 SD
Bars show Means
-1,0
-0,5
0,0
0,5
1,0
dis
tan
ce
, mm
first second
-1,0
-0,5
0,0
0,5
1,0
dis
tan
ce
, mm
Significant differences in tongue displacement sizes –
no significant differences in tongue displacement sizes –
/i/ vs /u/
/a/ vs /i/,
/a/ vs /u/
Average tongue shape pattern during /ihi/
Black solid line –V1
Red solid line –/h/ Blue dashed line –
V2
Average tongue shape pattern during /ihi/
Distances between V1, C and V2 curves, /ihi/
V1 /h/ V2Middle part of the tongue typically lowers during the consonant
!“Trough”!
Distances between V1, C and V2 curves, /ihi/
Back part of the tongue on average moves slightly backwards during the consonant
V1 /h/ V2
!Relaxation of Advanced Tongue Root!
Average tongue shape pattern during /uhu/
Black solid line –V1
Red solid line –/h/
Blue dashed line – V2
Average tongue shape pattern during /uhu/
Distances between V1, C and V2 curves, /uhu/
V1 /h/ V2Middle part of the tongue typically lowers during the consonant
!“Trough”!
Distances between V1, C and V2 curves, /uhu/
Tongue typically goes backwards from V1 into C, and forwards again for V2
V1 /h/ V2
!Relaxation of Advanced Tongue Root!
Average tongue shape pattern during /aha/
Black solid line –V1
Red solid line –/h/
Blue dashed line – V2
Average tongue shape pattern during /aha/
Distances between V1, C and V2 curves, /aha/
Front part of the tongue is on average lower for V2 than for V1
V1 /h/ V2
!Second syllable stressed!
/aha/ fewer number of troughs and their
significantly smaller size in /a/ than in the other two vowels
possible explanation:
for the open vowel /a/ raising, rather than lowering, would be expected during tongue deactivation (Lindblom et al. 2002, Vazquez Alvarez, Hewlett & Zharkova 2004)
/aha/
/aha//aha/
/aha/ /aha/ /aha/
Differences between V1 and V2 On average V1 is further away from C than V2,
suggesting a syllable boundary influence and showing asymmetrical nature of VCV:
ihi uhu aha
V1-C: 0,539 0,582 0,362
V2-C: 0,387 0,519 0,310
Conclusions Tongue is in a very similar position for both
vowels and /h/ However, there is some evidence that /h/ is
more like V2 than like V1: a syllable boundary effect
Some evidence for troughs, but they are small
More troughs in /i/ and /u/ contexts than in /a/ context
Troughs/antitroughs mainly occur in mid and back parts of the tongue
Front of the tongue – continuous movement from V1 to V2
Conclusions
Implications for the future Why these patterns? May be some properties of /h/ May be due to syllable boundary within the
VhV sequence May be due to stress position and its
physical characteristics
… Future research…..
Bell-Berti, F. & Harris, K.S. (1974). More on the motor organization of speech gestures. Haskins Labs. Status Rep. Speech Res., SR-37/38, pp. 73-77.
Engstrand, O. (1988). Articulatory correlates of stress and speaking rate in Swedish VCV utterances. Journal of the Acoustical Society of America, 83, pp. 1863-1875.
Fuchs, S., Hoole, P., Brunner, J. & Inoue, M. (2004). The trough effect – an aerodynamic phenomenon? [Oral presentation, “From Sound to Sense”, 11-13 June 2004, MIT.]
Gay, T. (1974). Some electromyographic measures of coarticulation in VCV utterances. Haskins Labs. Status Rep. Speech Res., SR-44, pp. 137-145.
Gay, T. & Ushijima, T. (1974). Effect of speaking rate on stop consonant-vowel articulation. Speech Commun. Semin., Stockh., SCS-74, pp. 205-208.
Houde, R.A. (1967). A study of tongue motion during selected speech sounds. PhD diss. Speech Commun. Res. Lab., Santa Barbara, Monogr. No. 2.
Karbownicki, L. (2004). Investigation of the coarticulation effects on [h] when preceding a vowel. BSc, Honours project, Queen Margaret University College.
Keating, P.A. (1988). Underspecification in phonetics. Phonology 5.2, pp. 275-292.
REFERENCES
Kozhevnikov, V.A. & Chistovich, L.A. (1965). Rech: Artikulyatsiya i vospriyatiye (Speech: Articulation and perception). Moscow-Leningrad. Translation: Kozhevnikov, V.A. & Chistovich, L.A. (1965). Speech: Articulation and perception, No. 30, p. 543 (Joint Pub. Res. Service, Washington).
Ladefoged, P. (2001). A Course in Phonetics. 4th edn. Orlando, FL: Harcourt College Publishers.
Lindblom, B., Sussman, H.M., Modaressi, G. & Burlingame, E. (2002). The trough effect: Implications for speech motor programming. Phonetica, 59, pp. 245-262.
Perkell, J. (1986). Coarticulation strategies: preliminary implications of a detailed analysis of lower lip protrusion movements. Speech Communication, 5, pp. 47-68.
Pierrehumbert, J. & Talkin, D. (1992). Lenition of [h] and glottal stop. In J. Docherty & D.R. Ladd (eds.), Papers in Laboratory Phonology II: Gesture, Segment, Prosody. Cambridge: Cambridge University Press. Pp. 90-117.
Svirsky, M., Stevens, K., Matthies, M., Manzella, J., Perkell, J. & Wilhelms-Tricarico, R. (1997). Tongue surface displacement during bilabial stops. Journal of the Acoustical Society of America, 102, pp. 562-571.
Vazquez Alvarez, Y., Hewlett, N., & Zharkova, N. (2004). An ultrasound study of the "Trough Effect". [Poster at the British Association of Academic Phoneticians Colloquium 2004, University of Cambridge, Cambridge, UK.]
REFERENCES
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