An MRI-based cross-linguistic study of sibilant fricatives

Martine Toda 1,2 & Kiyoshi Honda 1

1 ATR, Human Information Science Laboratories, Japan.2 Laboratoire de Phonétique et Phonologie UMR 7018,

Université Paris III / CNRS, France.

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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‘Sibilant fricatives’

• Fricatives produced with clenched teeth (or the upper teeth close to the lower lip) (Ladefoged and Maddieson, 1996)

• Acoustically characterized by a loud frication noise (Shadle, 1985)

• Distinguished each other by their noise spectrum (Harris, 1958)

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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Sibilant fricatives in Toda (a Dravidian language spoken in India), Ladefoged and Maddieson (1996, p.160)

Sibilants: a consonantal subsystem

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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Aims of the study

To examine• how sibilants are contrasted with each other in

articulation

and• how the articulatory space is delimited by

phonological features

Method

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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Languages, sibilants and subjects

unvoiced sibilant

fricatives

3 sibilants system

/ , / / , / / , , /

type of contrast palatalizationplace of

articulationboth

language Japanese French English Chinese Swedish

number of subjects

97 5 4 1

12 5

2 sibilants systems

front

contrast of place of articulation

back

contrast of place of articulation

palatalized

contrast of palatalization

not palatalized

contrast of palatalization

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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MRI data acquisition

• Sibilant fricatives– Sustained fricatives

– Supine position

• Teeth – tongue and lips kept tightly

close to teeth

directionscanned

arearesolution

slice thickness

and spacingTE TR

scan duration

sagittal128 mm 128 mm

45 mm

0.25 mm 0.25

mm1.5 mm 3.3 ms 10 ms 23 s

The Shimadzu-Marconi ECLIPSE 1.5T scanner at ATR’s Brain Activity Imaging Center

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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Redeeming teethoriginal MRI data

sibilants

teeth

merging teeth and articulatory data

The three data sets are manually fitted in Intage rv (KGT Inc.); Estimated precision: 0.25 mm and 0.5

extracted teeth shape

upper teeth

lower teeth

}

extraction helped by rough hand tracing

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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Articulatory measurements

place of articulation

mid-sagittal slice

tongue shape

palatalization index =front cavity area =

Results

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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front cavity area (mm2)

pala

taliz

atio

n in

dex

(mm

)

ssj

s

s

ellipses for 2

s

Fr.

Fr.

En.

Ch.

Ch.

Sw.

J.

J.

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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front cavity area (mm2)

pala

taliz

atio

n in

dex

(mm

)

ssj

s

s

ellipses for 2

sj and

Ch.

Ch.

Sw.

J.

J.

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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front cavity area (mm2)

pala

taliz

atio

n in

dex

(mm

)

ssj

s

s

ellipses for 2

and

Fr.

Fr.

En.

Ch.

Ch.

Sw.

Discussion

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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front cavity area (mm2)

pala

taliz

atio

n in

dex

(mm

)

ssj

s

s

ellipses for 2

Feature specification and articulatory space

s

sj

s

s

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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front cavity area (mm2)

pala

taliz

atio

n in

dex

(mm

)

ssj

s

s

ellipses for 2

Redundant feature specification

s

sj

s

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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front cavity area (mm2)

pala

taliz

atio

n in

dex

(mm

)

ssj

s

s

ellipses for 2

Inventory size and articulatory space

ss

Conclusion

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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Summary

• /s/ front, /sj and / long constriction, / and / back and // shorter constriction than // in 3 sibilants languages

• Articulatory space split into smaller parts when a feature (dimension) is consistent;

• Articulation specified for all consistent features even when redundant;

• Size of articulatory space do not directly depend on inventory size

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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Further challenges

• Refining articulatory measures– Measures of vocal tract shape => systematic

relationship with the acoustics

• Language-dependent articulatory space – why ?– Need to take into account a larger consonantal

subsystem ?

ISSP 2003 An MRI-based cross-linguistic study of sibilants

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Acknowledgement

• Thanks to:Chunyue Zhu

Alexis Michaud

Fredrik Bissmarck

• Work supported by the Telecommunications Advancement Organization of Japan