Phonation

Phonation is the production of sound by the vibration of the vocal folds in the larynx as air from the lungs passes through the glottis. It underpins voicing in most speech sounds.

Mechanism: Subglottal pressure forces the folds apart; tissue elasticity and the Bernoulli effect draw them back together, creating a repeating glottal cycle. The fluctuation of glottal opening intermittently modulates the airstream, generating a periodic voice signal. The mucosal wave on the folds helps sustain vibration and shapes the sound.

Control and acoustics: The fundamental frequency (F0) depends on the length, tension, and mass of the vocal folds, adjusted by intrinsic laryngeal muscles such as the cricothyroid and thyroarytenoid. Subglottal pressure and glottal closure also affect loudness and spectral characteristics, including harmonic richness and spectral tilt.

Phonation types: Modal voice is the typical speaking voice; creaky voice features low, irregular vibrations; breathy voice uses a partially open glottis; falsetto describes very high-pitched phonation; pressed or harsh voice involves strong medial compression.

Clinical relevance: Phonation is a focus in voice science, speech-language pathology, and otolaryngology. Disorders affecting phonation include dysphonia, nodules, polyps, laryngeal paralysis, and puberphonia; assessment and therapy aim to optimize voice quality and efficiency.