1. Anatomy of the vocal mechanism
Speech Production

2. Speech Production

3. Speech Production

4. Phonation Myoelastic aerodynamic theory of phonation.
Fundamental frequency
Harmonics
Speech Production

5. Phonation Production of sound in larynx.
Anytime you use voicing to produce a sound (e.g., vowels and voiced consonants) phonation will take place.
Myoelastic aerodynamic theory of phonation (see next slide)
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6. Myoelastic Aerodynamic Theory of Phonation
Two stage process
Stage one: Myoelastic phase. Elasticity of vocal folds helps them close.
Stage two: Aerodynamic phase
Sub-glottal pressure forces vocal folds apart
Bernoulli Effect helps vocal folds close
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7. Bernoulli Effect As air velocity increases, air pressure decreases.
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8. Myoelastic Aerodynamic Theory of Phonation (continued)
Another way of stating the MA theory is to see how vocal folds open and close.
Opened due to…
Increase in subglottal pressure
Closed due to…
Vocal fold elasticity
Bernoulli effect
Speech Production

9. Fundamental Frequency
Refers to the fundamental frequency to which the vocal folds vibrate at.
Variables that affect fundamental frequency (fo)
Gender and age
Males 120 Hz
Females 220 Hz
Children Hz
Mass (relaxing and tensing of vocal folds)
Intensity (Bernoulli effect)
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10. Harmonics Discussed during acoustics section. Remember…
During phonation you will fo along with a series of harmonics
Spacing between harmonics will equal the fo.
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11. Harmonics
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12. Jitter and Shimmer Jitter Shimmer
Variations in the Fo, aka frequency perturbation
Periods between individual cycles vary slightly (e.g., 200, 201, 199 Hz, etc.)
Shimmer
Variations in Intensity, aka amplitude perturbation
Speech Production

13. Jitter and Shimmer continued
Causes of jitter and shimmer
Neurological
Biomechanical
Aerodynamic
Acoustic (hearing loss)
Normal values
Jitter (0.2 to 1%) of frequency
Shimmer (< 0.5 dB)
Speech Production

14. Jitter and Shimmer continued
Clinical Applications
Vocal aging
Increased for children and elderly
Neurological pathology
Parkinson’s Disease
Amyotrophic Lateral Sclerosis
Laryngeal Cancer
Increased vocal fold mass (e.g., nodule, polyp, etc.)
Stuttering in young children (shimmer)
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15. Vocal Registers
Pulse
Modal
Midvoice
Falsetto
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16. Pulse
• Vocal frequency is 30 to 80 Hz in males and 90 to 165 Hz in females.
VFs are closed about 90% or time and open 10%.
Perceived as burst of acoustic energy but with silence gaps.
Normal at end of phrases and sentences.
Clinical problem if used habitually.
Speech Production

17. Modal and Midvoice Modal Midvoice About 100 to 150 Hz in males
About 175 to 300 Hz in females
Perceived as normal speech
Midvoice
About 200 to 300 Hz in males
About 350 to 600 Hz in females
Often used in singing situation
Speech Production

18. Falsetto Vocal frequency of about 350 to 500 Hz in males.
About 650 to 1000 Hz in females.
Vocal folds may not meet in middle because of abnormal tension and may be breathy
“Reedy sound” due to widely spaced harmonics.
Falsetto’s are not a part of normal speech.
Speech Production

19. Summary
Speech Production