Phonology Physiology

Abduction (vocal folds)

Movement in which the vocal folds separate/open to allow airflow for breathing.

Abdominal fixation

Trapping of air in the thorax to stabilize the torso for heavy lifting or childbirth.

Adduction (vocal folds)

Movement in which the vocal folds come together/close to trap air or produce voice.

Amplitude

Extent of vocal-fold excursion during vibration.

Anterior Commissure

Fixed anterior point where the true vocal folds attach to the inside of the thyroid cartilage.

Aphonia

Complete loss of the ability to produce voice.

Aspiration

Entry of food or liquid into the airway below the vocal folds.

Aryepiglottic Muscle

Auxiliary muscle that constricts laryngeal opening by pulling arytenoid apices toward epiglottis; RLN innervated.

Arytenoid Cartilages

Paired pyramidal cartilages atop cricoid that anchor and move the vocal folds.

Average fundamental frequency

Mean F0 across a speech sample such as reading passage or conversation.

Bernoulli effect

Drop in pressure and increase in airflow velocity at a constriction, helping suck vocal folds back together.

Breathy vocal attack

Significant airflow begins before the vocal folds adduct.

Breathy phonation

Voice with incomplete glottal closure allowing audible air escape.

Cricoarytenoid Joint

Synovial joint between cricoid and arytenoid cartilages that rocks, glides, and slightly rotates to abduct or adduct the vocal folds.

Cricothyroid Muscle

Primary tensor consisting of pars recta and pars oblique; rocks thyroid forward to stretch the folds, raising pitch; SLN (external) innervation.

Cricothyroid Joint

Synovial joint between cricoid and thyroid cartilages that rocks and glides to stretch the vocal folds and raise pitch.

Coughing

Forceful expiratory reflex that clears material from the top of the airway.

Cycle

One complete opening-closing movement of the vocal folds.

Decibel (dB)

Unit used to quantify sound intensity.

Diadochokinetic rate (DDK)

Speed of rapid, alternating articulatory movements (e.g., /pʌ tʌ kʌ/).

Digastric Muscle (Anterior Belly)

Suprahyoid muscle that draws hyoid up and forward; innervated by trigeminal nerve (CN V).

Digastric Muscle (Posterior Belly)

Suprahyoid muscle that draws hyoid up and back; innervated by facial nerve (CN VII).

Dysphonia

Any disorder of voice quality, pitch, or loudness caused by impaired vocal fold function.

Elasticity

Tendency of vocal-fold tissue to return to its original shape after being displaced.

Electrolarynx

Hand-held vibrating device placed on the neck to create an artificial voice.

Epiglottis

Leaf-shaped cartilage that folds over the airway during swallowing to protect the lungs.

Esophageal speech

Voice substitution method using air injected into the esophagus to create sound.

Extrinsic Laryngeal Muscles

Muscles with one attachment outside the larynx; elevate or depress the larynx and hyoid for larger positioning movements.

False (Ventricular) Vocal Folds

Fold of tissue located above the true vocal folds; usually do not vibrate during normal speech.

Falsetto

High-pitch register using elongated, thin, tense vocal folds.

Flexible fiberoptic endoscopy

Thin, pliable scope passed through the nose for dynamic viewing of vocal-fold function.

Frequency

Number of vibratory cycles per second, measured in hertz (Hz).

GERD (Gastroesophageal Reflux Disease)

Backflow of stomach acid that can irritate laryngeal tissues and alter voice.

Geniohyoid Muscle

Slender suprahyoid muscle that elevates hyoid and depresses mandible; innervated by C1 via hypoglossal nerve (CN XII).

Genioglossus Muscle

Large tongue muscle that can elevate hyoid when tongue is fixed; CN XII innervated.

Glottal attack

Vocal folds adduct before airflow; includes the hard glottal attack.

Glottal fry (pulse register)

Low-pitch, crackly register characterized by short, thick folds and low airflow.

Glottis

The space between the vocal folds; opens and closes during phonation.

Habitual pitch

Pitch level most frequently used in everyday speech.

Hyoid Elevators

Muscles that raise the hyoid bone, assisting laryngeal elevation (suprahyoid group).

Hyoid Depressors

Muscles that lower the hyoid bone, aiding laryngeal depression (infrahyoid group).

Hyoglossus Muscle

Tongue-and-hyoid connector that elevates hyoid and depresses tongue; CN XII innervated.

Infrahyoid Muscles

Group of extrinsic muscles that attach below the hyoid and depress the hyoid/larynx (e.g., sternohyoid, omohyoid, sternothyroid).

Inertia

Property that keeps a moving mass (e.g., vocal fold) in motion until another force acts on it.

Intensity

Acoustic power of the voice signal; measured in decibels (dB).

Intonation

Pitch variation across an utterance that signals meaning or emotion.

Intrinsic Laryngeal Muscles

Muscles with both origin and insertion on laryngeal cartilages; control fine adjustments for phonation (adduct, abduct, tense, relax).

Jitter

Cycle-to-cycle variability in frequency; reflects pitch stability.

Laryngeal Elevators

Muscles that raise the entire laryngeal framework, important in swallowing and pitch increase.

Laryngeal palpation

Manual assessment of laryngeal height and muscular tension via external neck touch.

Laryngeal Pitch Adjustment

Change in vocal pitch achieved mainly by stretching (tensing) or shortening (relaxing) the vocal folds.

Laryngeal Depressors

Muscles that lower the larynx within the neck, aiding in pitch lowering and post-swallow reset.

Laryngeal trauma

Physical injury to the larynx from external events (accident, assault, sports).

Laryngectomy

Surgical removal of part or all of the larynx, often for cancer treatment.

Lateral Cricoarytenoid Muscle

Intrinsic adductor that rocks arytenoids inward/downward to adduct and lengthen the vocal folds; RLN innervated.

Longitudinal tension

Extent of vocal-fold stretching along their length.

Loudness

Psychological correlate of intensity.

Mass effect on frequency

As vocal-fold mass increases, frequency (and pitch) decrease, and vice versa.

Maximum phonation time (MPT)

Longest duration a person can sustain a vowel on a single breath.

Medial Compression

Degree of force with which vocal folds are pressed together; increased by adductor muscles for louder phonation.

Medial compression

Force with which the vocal folds are pressed together at midline.

Modal register

Typical register used in conversational speech.

Monoloudness

Lack of normal loudness variation during speech.

Monopitch

Lack of normal pitch variation during speech.

Mylohyoid Muscle

Fan-shaped floor-of-mouth muscle elevating hyoid or depressing mandible; mandibular branch of CN V innervated.

Myoelastic-Aerodynamic Theory

Explains phonation as interaction of muscular tension, tissue elasticity and aerodynamic forces.

Neoplasm

New tissue growth in the larynx; may be benign or malignant (cancerous).

Oblique Arytenoid Muscle

Paired intrinsic adductor running in an “X” pattern; pulls arytenoid apices medially and up; RLN innervated.

Omohyoid Muscle (Inferior Belly)

Lower section of omohyoid originating on scapula; joins intermediate tendon to assist hyoid depression.

Omohyoid Muscle (Superior Belly)

Upper section of infrahyoid muscle that depresses hyoid; cervical ansa innervated.

Optimal pitch

Pitch that is most efficient and least taxing for an individual’s vocal mechanism.

Parkinson’s voice changes

Reduced intensity, monopitch and breathy quality due to degenerative motor disease.

Pars Recta

Vertical part of the cricothyroid that lengthens the vocal folds by rocking the thyroid cartilage downward in front.

Pars Oblique

Oblique part of the cricothyroid that slides the thyroid forward, tensing the vocal folds.

Period

Time required to complete one vibratory cycle.

Periodic wave

Waveform that repeats in a predictable pattern over time.

Phonation

Process of producing voiced sound through vibration of the true vocal folds.

Pitch

Psychological (perceptual) correlate of frequency.

Pitch range

Difference between the highest and lowest usable pitches of a speaker.

Posterior Cricoarytenoid Muscle

Sole intrinsic abductor that opens the vocal folds by rocking arytenoids laterally; RLN innervated.

Pressed phonation

Voice produced with excessive medial compression, yielding a harsh, strained quality.

Presbyphonia

Age-related changes resulting in an older-sounding, weaker voice.

Presbylaryngis

Structural aging of the laryngeal tissues and cartilages.

Prosody

Suprasegmental features—rhythm, stress, pitch and pauses—that convey expression.

Protective function (larynx)

Primary, life-saving role of the larynx that prevents foreign material from entering the lungs.

Recurrent Laryngeal Nerve (RLN)

Branch of the vagus that loops under the aorta/subclavian and innervates all intrinsic laryngeal muscles except cricothyroid; vulnerable in heart/thoracic surgery.

Rigid endoscopy

Straight, metal scope inserted orally to provide high-resolution images of the vocal folds.

Shimmer

Cycle-to-cycle variability in vocal-signal amplitude; reflects loudness stability.

Simultaneous vocal attack

Adduction of the folds and onset of exhalation occur together.

Sound level meter

Instrument that objectively measures vocal intensity in dB.

Stiffness

Internal resistance of vocal-fold tissue to deformation.

Sternothyroid Muscle

Infrahyoid muscle that depresses thyroid cartilage and, by extension, the larynx; innervated by CN XII & C1–C2.

Sternohyoid Muscle

Infrahyoid strap muscle from sternum to hyoid that depresses the hyoid; cervical ansa innervation.

Stylohyoid Muscle

Suprahyoid muscle from styloid process to hyoid; retracts hyoid posteriorly; CN VII innervated.

Subglottal space

Area below the vocal folds within the larynx.

Subglottal pressure

Air pressure below the vocal folds necessary to initiate and sustain phonation.

Superior Laryngeal Nerve (SLN)

Vagus branch whose external division innervates the cricothyroid muscle and internal division provides laryngeal sensation above the folds.

Supraglottal space

Area above the vocal folds within the larynx.

Suprahyoid Muscles

Group of extrinsic muscles that attach above the hyoid and elevate the hyoid/larynx (e.g., digastric, stylohyoid, mylohyoid, geniohyoid).

Sustained phonation

Maintenance of steady vocal-fold vibration after attack phase.