Related Experiment Video
Updated: Aug 6, 2026
08:32
Ultrasound Images of the Tongue: A Tutorial for Assessment and Remediation of Speech Sound Errors
Published on: January 3, 2017
Tongue surface displacement during bilabial stops
M A Svirsky1, K N Stevens, M L Matthies
1Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge 02139, USA.
The Journal of the Acoustical Society of America
|July 1, 1997
Summary
Tongue movement during speech differs between voiced and voiceless bilabial stops. Greater tongue displacement and compliance were observed during voiced /b/ sounds compared to voiceless /p/ sounds, suggesting active muscle control.
Area of Science:
- Speech Production
- Articulatory Phonetics
- Bioacoustics
Background:
- Understanding vocal tract wall impedance is crucial for accurate speech production models.
- Previous estimates of vocal tract wall impedance lack direct measurements of tongue displacement during closure.
- The role of passive versus active vocal tract enlargement during voicing remains debated.
Purpose of the Study:
- To measure tongue surface displacement during bilabial stop consonant production (/b/ and /p/).
- To refine vocal tract wall impedance estimates using direct tongue displacement data.
- To investigate active versus passive vocal tract enlargement during voicing.
Main Methods:
- Measured tongue displacement in four subjects during the production of /aba/ and /apa/.
- Estimated tongue compliance based on displacement and intraoral pressure waveforms.
- Analyzed intraoral pressure and tongue displacement data to infer muscle activity.
Main Results:
- Significantly greater tongue displacement occurred during voiced /aba/ compared to voiceless /apa/, despite lower peak intraoral pressure for /aba/.
- Tongue compliance estimates were substantially higher for /aba/ (5.1–8.5 x 10^-5 cm³/dyn) than for /apa/ (0.8–2.3 x 10^-5 cm³/dyn).
- Smaller tongue displacements for /p/ suggest potential active tongue stiffening or muscle relaxation during /b/.
Conclusions:
- Direct measurements of tongue displacement provide refined estimates of vocal tract wall impedance.
- Differences in tongue displacement and compliance between voiced and voiceless stops indicate active articulatory adjustments.
- Findings support the hypothesis of active tongue stiffening during voiceless stops or muscle relaxation during voiced stops.
