SPPA 6010 Advanced Speech Science Phonation SPPA 6010 Advanced Speech Science

Laryngeal Activity in Speech/Song Sound source to excite the vocal tract Voice Whisper Prosody Fundamental frequency (F0) variation Amplitude variation Realization of phonetic goals Voicing Devoicing Glottal frication (//, //) Glottal stop (//) Aspiration Para-linguistic and extra-linguistic roles Transmit affect Speaker identity SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Topic Sequence Basic Laryngeal Anatomy Myoelastic-aerodynamic theory of phonation Basic Features of Phonation Frequency and Intensity Control Other Phonatory Parameters Instrumentation SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Behrman Chapter 5, 6 Place less emphasis on… Minor anatomical landmarks and features Extrinsic muscles of the larynx Blood supply to the larynx Central motor control of larynx Peripheral Sensory control of larynx Stress-Strain Properties of Vocal Folds SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Location of Larynx SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Bones Hyoid Bone Key Cartilages Thyroid cartilage Cricoid cartilage Epiglottis Arytenoid cartilages SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Cricoarytenoid Joint Cricothyroid Joint SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Key structures esophagus posterior arytenoid glottis Pyriform sinus True vocal fold aryepiglottic fold False (ventricular) fold epiglottis anterior SPPA 6010 Advanced Speech Science

Intrinsic Laryngeal muscles Key Actions Adduct Abduct Tense Slacken Lengthen Shorten ADDUCTION not independent of each other ABDUCTION SPPA 6010 Advanced Speech Science

Intrinsic Laryngeal muscles Lateral cricoarytenoid (LCA) (Inter)arytenoid (IA) Posterior cricoarytenoid (PCA) Thyroarytenoid (TA) Cricothyroid (CT) Principal Actions Adducts Abducts Shorten/slack-tense Lengthen/tenses SPPA 6010 Advanced Speech Science

Extrinsic/Supplementary muscles Suprahyoid muscles Digastric Mylohyoid Geniohyoid Stylohyoid Infrahyoid muscles Thyrohyoid Sternothyroid Sternohyoid Omohyoid SPPA 6010 Advanced Speech Science

Extrinsic/supplementary muscles Holds the larynx in the neck Allows positional change of the larynx Elevates when swallowing Elevates during certain speech activities Elevating pitch High vowel production SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Layers of Vocal Fold Cover epithelium superficial layer (Reinke’s space) Transition Area intermediate layer deep layer Body TA muscle Lamina Propria (LP) vocal ligament SPPA 6010 Advanced Speech Science

The vocal fold through life… Newborns No layered structure of LP LP loose and pliable Children Vocal ligament appears 1-4 yrs 3-layered LP is not clear until 15 yrs Old age Superficial layer becomes edematous & thicker Thinning of intermediate layer and thickening of deep layer Changes in LP more pronounced in men Muscle atrophy SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Topic Sequence Basic Laryngeal Anatomy Myoelastic-aerodynamic theory of phonation Basic Features of Phonation Frequency and Intensity Control Other Phonatory Parameters Instrumentation SPPA 6010 Advanced Speech Science

Myoelastic Aerodynamic Theory of Phonation Necessary and Sufficient Conditions Vocal Folds are adducted (Adduction) Vocal Folds are tensed (Longitudinal Tension) Presence of Aerodynamic pressures SPPA 6010 Advanced Speech Science

2-mass model Upper part of vocal fold Mechanical coupling stiffness Lower part of vocal fold Coupling between mucosa & muscle TA muscle

SPPA 6010 Advanced Speech Science VF adducted & tensed → myoelastic pressure (Pme ) Glottis is closed subglottal air pressure (Psg) ↑ Psg ~ 8-10 cm H20, Psg > Pme L and R M1 separate Transglottal airflow (Utg) = 0 As M1 separates, M2 follows due to mechanical coupling stiffness Psg > Pme glottis begins to open Psg > Patm therefore Utg > 0 SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Utg ↑ ↑ since glottal aperature << tracheal circumference Utg ↑ Ptg ↓ due to Bernoulli effect Pressure drop across the glottis Bernoulli’s Law P + ½ U2 = K where P = air pressure  = air density U = air velocity SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Utg ↑ Ptg ↓ due to Bernoulli effect Ptg < Pme M1 returns to midline M2 follows M1 due to mechanical coupling stiffness Utg = 0 Pattern repeats 100-200 times a second SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science

Limitations of this simple model Actual VF movement is more complex Vocal folds have length and vary in biomechanical properties along their length SPPA 6010 Advanced Speech Science

Complexity of vocal fold vibration Vertical phase difference Longitudinal phase difference SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Vibratory Complexity SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Topic Sequence Basic Laryngeal Anatomy Myoelastic-aerodynamic theory of phonation Basic Features of Phonation Frequency and Intensity Control Other Phonatory Parameters Instrumentation SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Glottal area waveform SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Flow Glottogram SPPA 6010 Advanced Speech Science

Phonatory Behavior: Aerodynamic Features Volume Velocity Driving Pressure Laryngeal Airway Resistance Phonation Threshold Pressure Initiate phonation Sustain phonation SPPA 6010 Advanced Speech Science

Acoustic consequence of vocal fold vibration Air disturbance is caused by the “slapping” together of the vocal folds Sound energy is maximum at glottic closure Given the complexity of the vibratory patterns of the vocal fold, the sound produced at the glottis is complex and periodic. SPPA 6010 Advanced Speech Science

Glottal waveform (Time domain) ‘triangular’ shaped Looks simple, but is complex SPPA 6010 Advanced Speech Science

Glottal waveform (Frequency domain) Harmonics have a 12 dB/octave roll off SPPA 6010 Advanced Speech Science

The real deal: Phonation is actually quasi-periodic Contains two components Periodic Complex periodic Harmonic structure 12 dB/octave roll off Aperiodic Broad frequency noise embedded in signal SPPA 6010 Advanced Speech Science

Sources of aperiodicity Non-periodic vocal fold oscillation Inappropriate combination of Psg and Pme Mucosal disease, neuromuscular disease, poor fluid balance, etc Asymmetry of vocal fold oscillation Anatomical asymmetry Unilateral paralysis/paresis, mucosal lesion, Air turbulence due to Open phase Incomplete glottal closure SPPA 6010 Advanced Speech Science

SPPA 6010 Advanced Speech Science Voicing vs. Whispering SPPA 6010 Advanced Speech Science