A voice disorder is any change in the voice which affects the sound of the voice and ability to communicate in everyday situations. Voice disorders may occur from inappropriate use of the voice, medical conditions, following illness, damage to the nerves supplying the larynx, injury to the larynx, or from neurological disorders.
Voice production relies on the interaction of the respiratory, laryngeal, resonance, and articulation systems and is controlled by the nervous system. The vocal folds are set into vibration, creating sound waves, as air is directed through the larynx from the lungs. The tension, mass, and shape of the vocal folds, as well as the shape of the vocal tract, will determine the pitch, loudness, and quality of the voice.