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Subglottal coupling and its influence on vowel formants
Xuemin Chi1, Morgan Sonderegger
1Speech Communication Group, RLE, MIT, Cambridge, Massachusetts 02139, USA. xuemin@speech.mit.edu
The Journal of the Acoustical Society of America
|October 12, 2007
Summary
Acoustic coupling between oral and subglottal cavities affects vowel sounds. This study models how subglottal resonances influence vowel formant prominence, potentially explaining front-back vowel distinctions.
Area of Science:
- Acoustic phonetics
- Speech science
- Physiological phonetics
Background:
- Acoustic coupling between oral and subglottal cavities influences speech production.
- Subglottal resonances may play a role in phonemic distinctions, such as front vs. back vowels.
Purpose of the Study:
- To develop and validate a model of acoustic coupling between the oral and subglottal cavities.
- To investigate the influence of subglottal resonances on vowel formant prominence.
- To test the hypothesis that subglottal resonances act as a quantal effect distinguishing front and back vowels.
Main Methods:
- Developed an acoustic resonator model for oral-subglottal coupling.
- Recorded English vowels (/hVd/) from six speakers (3 male, 3 female).
- Measured subglottal waveforms using an accelerometer on the neck.
Main Results:
- The model predicts attenuation and discontinuities in vowel formant prominence near subglottal resonances.
- Observed attenuation of 5-12 dB in second formant prominence near the second subglottal resonance (SubF2) for back-front diphthongs.
- Measured SubF2 values (1280-1620 Hz) align with model predictions and prior research.
- Observed discontinuities (50-300 Hz) agree well with the resonator model.
- Coupling effects were stronger for open-phase than closed-phase measurements.
Conclusions:
- Acoustic coupling significantly impacts vowel acoustics, particularly near subglottal resonances.
- The second subglottal resonance (SubF2) appears to be a quantal effect influencing the distinction between front and back vowels.
- The findings support the role of physiological constraints in shaping phonemic contrasts.
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