Anatomic Aspects

1. Anatomic Aspects • Glottis: Slit like opening between folds • Folds move and change tension • Vocal folds and epiglottis close during eating (also false vocal folds) • False vocal folds are likely open during speech prouction • Larynx: Sytem of muscles, cartileges and ligaments. • Primarly for controlling vocal folds • Folds 13-15mm

3. LarynxTop View Voicing Breathing

4. Three Primary States of Vocal Folds: Breathing, Voiced and Unvoiced • BREATHING: Arytenoid cartileges move outward, fold muscles are relaxed. • VOICING:The size/mass and tension of folds determines pitch (60-400 Hz) MOTION OF FOLDS DURING VOICING

5. Mechanical Model of Folds

6. Periodic Glottal Flow Velocity

7. Mathematical Model of Glottal Flow Impulse train Glottal flow over a single cycle (imp. Resp.) Glottal flow waveform P : pitch period Looking through a small window Absence of window would yield impulses

8. Practical Phenomena • Fixed pitch is not possible even in sustained cases  “pitch jitter” • Airflow velocity within a glottal cycle may differ across consecutive periods  “shimmer” • Jitter and shimmer yield “naturalness” and contributes to the “voice character”.

9. UNVOICING no vibration of vocal folds Folds are close to each other but open and tense  Turbulance / aspiration /h/ whisper • Aspiration normally occurs during voicing also. • If strong  breathy voice.

10. Other Forms of Vocal Fold Movement • Creaky Voice: Folds are very tense and vibrating part is small. • It is a harsh sounding voice. • High and irregular pitch is observed. • Vocal Fry: When folds are massy and relaxed. • Abnormally low and irregular pitch. • Secondary glottal pulses arise within the open phase • Folds may couple with false vocal folds. • Vocal fry may ocur in normal speech at the edn of a phrase when folds relax and lung pressure decreases. • Diplophonic: Secondary pulses in the closed phase. • Generally in low pitch speakers. • It may arise in normal voices at the end of a phrase or word. • Vocal fry and diplophonic can be modelled as

11. Vocal Fry Diplophonic

12. formant Related to bandwidth Vocal Tract ~17 cm and up to ~20 cm2 • Vocal tract colors the source • It also generates new sources for sound production • It can be approximated by a linear filter. • Resonance frequencies are called “formants” • Formant bandwidth and formant amplitude. • The peaks of the spectrum of vocal tract response are approximately formants.

13. All-pole model • ck : pole, resonance freq., formant • Formants: F1, F2, ... From low-to-high • In general, formant frequencies decreaseas vocal tract length increases. (male, female, child)

14. Vocal Tract Output Vocal tract impulse response In a small window (to pick a stationary portion)

16. Vowels Consonants Transitional Front Nasals Semi-Vowels Plosives Affricates chew just Center Diphtongs hide boy out new Back Whispers Fricatives Liquids read let Voiced Glides we you Unvoiced Voiced Unvoiced Speech Sounds - Phonemes • Broad classification is “vowels” and “consonants”. • Finer classification:

17. Vowels: No constriction along the vocal tract. • Voiced. Vocal folds vibrate. • Front, center or back; according to the tongue position. • Rounded, unrounded according to the position of lips. • Also, high-low according to tongue height. • Normal breathing yields low sound. The high intensity of vowels is because of vocal fold vibration.

18. Vowels

19. Fricatives

20. Plosives

21. Nasals

22. Transitional Sounds Spectrogram of the diphtong /O/ in “boy”.