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

Triggered by: 1. Recent research on troughs in VCV

sequences like /aba/

2. What we know about /h/:

/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

/aha/

/ihi/

/uhu/

Creating three annotations: mid /h/, V1, V2

Analysis

mid V1 mid /h/ same distance /h/ - V2

Creating three splines – V1, /h/, V2:

Analysis

splines superimposed on each other:

Analysis

Typical tongue contours during /uhu/

mid V1

mid V2

mid C

1. Comparing occurrence of different tongue shape patterns

Analysis

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

Results

2. Distances of tongue movement throughout VhVs

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/

3. Comparison of whole contour shapes

tongue contours, by vowel…

Results

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/

/aha/

One obvious and rather consistent pattern:

/aha/

/aha/

/aha/

/aha//aha/ /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/

Distances between V1, C and V2 curves

ihi

aha

V1 /h/ V2

uhu

Distances between V1, C and V2 curves

ihi

aha

V1 /h/ V2

uhu

Distances between V1, C and V2 curves

ihi

aha

V1 /h/ V2

uhu

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.]

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