The voice is produced as air from the lungs moves up through and vibrates the vocal cords. This is called phonation. The voice is then changed as it travels up through the different-shaped spaces of the throat, nose, and mouth. This is called resonance. Voice disorders include both phonation and resonance disorders:
- Phonation Disorders The voice may be harsh, hoarse, raspy, cut in and out, or show sudden changes in pitch with phonation disorders. Voice disorders can be due to vocal nodules, papillomas, ulceration, a laryngeal web, paralysis or weakness of the vocal cords, or difficulty timing breathing for speech.
- Resonance Disorders These are caused by an imbalance in sound energy as the voice passes through the spaces of the throat, nose, or mouth. When parents report that their child’s voice sounds “nasal” they are usually hearing one of two different types of resonance disorder:
- If the voice is hoarse, harsh, breathy, or of poor quality
- If the voice is always too loud or too soft
- If the voice is too high or too low for the child's age or sex
- If the voice often breaks or suddenly changes pitch
- If the voice sounds hyponasal or hypernasal