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Laryngeal Function and Speech ProductionLearning ObjectivesDescribe the basic role of the larynx in speech and song.

What is the basic role of the larynx in speech and songSound source to excite the vocal tractVoiceWhisperProsodyFundamental frequency (F0) variationAmplitude variationRealization of phonetic goalsVoicingDevoicingGlottal frication (//, //)Glottal stop (//)AspirationPara-linguistic and extra-linguistic rolesTransmit affectSpeaker identity3Learning ObjectivesPossess a knowledge of laryngeal anatomy sufficient to understand the biomechanics, aerodynamics and acoustics of phonation.

SPPA 4030 Speech Science5The hyo-laryngeal complex

5SPPA 4030 Speech Science6Extrinsic/Supplementary Muscles

6SPPA 4030 Speech Science7Intrinsic muscles

7SPPA 4030 Speech Science8Muscular Actions

8SPPA 4030 Speech Science9CA joint function

9SPPA 4030 Speech Science10Muscular actions on vocal foldsAlter positionAdductionLCA, IA, TAAbductionPCAAlter tension (and length)Increase/decrease longitudinal tensionBalance between TA and CT10SPPA 4030 Speech Science11Extrinsic/supplementary musclesHolds the larynx in the neckAllows positional change of the larynxElevates when swallowingElevates during certain speech activitiesElevating pitchHigh vowel production11SPPA 4030 Speech Science12The larynx

12SPPA 4030 Speech Science13Layered structure of vocal fold

13SPPA 4030 Speech Science14Basic Structure of the vocal foldepitheliumconnective tissuesuperficial layertissue loosely connected to the other layersintermediate layerelastic fibersdeep layercollagen fibers (not stretchy)muscle (TA)Vocal ligamentLaminapropria14The vocal fold through lifeNewbornsNo layered structure of LPLP loose and pliableChildrenVocal ligament appears 1-4 yrs3-layered LP is not clear until 15 yrsOld ageSuperficial layer becomes edematous & thickerThinning of intermediate layer and thickening of deep layerChanges in LP more pronounced in menMuscle atrophy

15Learning ObjectivesDescribe the control variables of laryngeal function.Laryngeal Opposing PressurePressure that opposes translaryngeal air pressureSourcesMuscular pressureSurface tensionGravity

Laryngeal Airway Resistance (LAR)Components of LARTranslaryngeal pressureTranslaryngeal flowValues can vary widelyResistance=Pressure/Flow

Glottal Size

Vocal Fold Stiffness

Effective Mass and Length

Learning ObjectivesOutline and briefly describe the different types of sounds that can be produced by the larynx.

Laryngeal Sound GenerationTransient vs. ContinuousGlottal stopsAperiodic vs. PeriodicGlottal fricativesWhisperingVoice production/phonation

Laryngeal Sound Generation

Glottal stopGlottal fricativeLearning ObjectivesDescribe a single cycle of vocal fold oscillationDescribe why phonation is considered quasi-periodicDescribe the relationship between vocal fold motion (kinematics), laryngeal aerodynamics and sound pressure wave formationDescribe and draw idealized waveforms and spectra of the glottal sound source

Complexity of vocal fold vibration

Vertical phase difference

Longitudinal phase difference26

The Glottal Cycle27Phonation is actually quasi-periodicComplex Periodicvocal fold oscillationAperiodicBroad frequency noise embedded in signalNon-periodic vocal fold oscillationAsymmetry of vocal fold oscillation Air turbulence28Flow Glottogram

29Synchronous plots

Sound pressure waveform(microphone at mouth)Glottal Airflow(inverse filtered mask signal)Glottal Area(photoglottogram)Vocal Fold Contact(electroglottogram)30Sound pressure wave

TimeInstantaneoussound pressure31Learning ObjectivesExplain vocal fold motion using the 2-mass model version of the myoelastic-aerodynamic theory of phonationGlottal Aerodynamics: Some TerminologySubglottal pressureTranslaryngeal Pressure (Driving Pressure)Translaryngeal Airflow (Volume Velocity)Laryngeal Airway ResistancePhonation Threshold PressureInitiate phonationSustain phonation

33Myoelastic Aerodynamic Theory of PhonationNecessary and Sufficient ConditionsVocal Folds are adducted (Adduction)Vocal Folds are tensed (Longitudinal Tension)Presence of Aerodynamic pressures (driving pressure)34

2-mass modelLower part of vocal foldUpper part of vocal foldMechanical coupling stiffnessTA muscleCoupling between mucosa & muscle35Definitions of termsPme : myoelastic pressure (aka laryngeal opposing pressure)Psg : subglottal pressurePatm: atmospheric pressurePwg : pressure within the glottisUtg : transglottal (translaryngeal) airflow

VF adducted & tensed myoelastic pressure (Pme )Glottis is closedsubglottal air pressure (Psg) Psg ~ 8-10 cm H20, Psg > Pme L and R M1 separateTransglottal airflow (Utg) = 0

As M1 separates, M2 follows due to

mechanical coupling stiffnessPsg > Pme

glottis begins to openPsg > Patm therefore Utg > 037

Utg since glottal aperature