A communication disorder characterized by abnormal vocal pitch, loudness, quality, tone, or resonance of enough severity to interfere with educational or occupational achievement or with social communication. Unlike other communication disorders, voice disorder may not appear until adulthood.
Abnormal acoustic qualities in a person’s speech, characterized by differences in pitch, loudness, or quality in comparison with others of the same age and gender.
Voice disorders are defined as the abnormal production or the absence of vocal characteristics such as quality, pitch, loudness, resonance, and duration. The determination of the existence of a voice disorder takes into account the individual’s age and sex (American Speech-Language-Hearing Association, 1993). Vocal quality refers to how well the vocal folds vibrate in synchrony. The pitch of one’s voice can either be too high or too low and depends upon the mass, length, and tension of the vocal folds. Loudness refers the volume of the voice—too loud or too soft. Vocal resonance pertains to the degree that sounds are altered as they travel through the pharyngeal, oral, and nasal cavities. Disorders of nasal resonance are the most common and result in a voice that is characterized by too much nasal resonance (hypernasality) or too little nasal resonance (hyponasality).