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Voice Disorders. A voice disorder is when the voice has a problem with pitch, volume, tone, and other qualities. These problems occur when the vocal cords don't vibrate normally. Your voice is the sound that air makes when it is forced out of your lungs and passes over your vocal cords.
1 Dysphonia, which is a speech disorder that gives a hoarse quality to the voice. 2  It can be caused by an injury to the nerve that affects the voice box (larynx) or a tumor in the brain stem. 3  It also has other possible causes that are not related to nervous system problems.