Anatomy of the vocal mechanism Speech Production

Speech Production

Speech Production

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

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) Speech Production

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 Speech Production

Bernoulli Effect As air velocity increases, air pressure decreases. Speech Production

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

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 270-300 Hz Mass (relaxing and tensing of vocal folds) Intensity (Bernoulli effect) Speech Production

Harmonics Discussed during acoustics section. Remember… During phonation you will fo along with a series of harmonics Spacing between harmonics will equal the fo. Speech Production

Harmonics Speech Production

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

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

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) Speech Production

Vocal Registers Pulse Modal Midvoice Falsetto Speech Production

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

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

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

Summary Speech Production