As everyone's voice is unique it is difficult to define a normal voice. A normal voice is pleasant sounding and has age and sex appropriate pitch and loudness. When a voice is not pleasant sounding, is too loud or too soft or is too high or low for one's gender, a voice problem may be present.

Voice disorder are divided into 2 categories: organic voice disorders and functional voice disorders. Organic voice disorders stem form disease or pathology. They require medical intervention. Functional voice disorders result from abuse or misuse of the voice. They can often be managed by voice therapy.

Voice is produced when the vocal folds (often called vocal cords) come close together and air from the lungs sets them vibrating in a regular fashion. The vibration causes a series of pulses which in turn causes the air column in the vocal tract to resonate and produce voiced sound.

When we are breathing, our vocal folds are open (abducted), and air passes by without vibrating them. Some sounds (e.g., s, sh, f) are produced without voice. When the vocal folds are brought together (adducted), the air pushes against the small opening and makes them vibrate, producing voicing. All vowels and some consonants (e.g., z, v, g) are voiced. Put your hand on your neck over your adam's apple. Say "aaaahhh" and feel the vibration in your voice box. Say a long "sssss": there should be no vibration.

Organic voice disorders include cancer, vocal fold paralysis, endocrine changes, granuloma, hemangioma, papilloma and laryngeal web.

Functional voice disorders arise when the voice is used improperly. Misuse of the voice includes talking too much or too loudly, yelling, or using an unnatural pitch (faking a deep or high voice). Abuse occurs with nonverbal vocal behavior such as excessive throat clearing, laughing, crying, coughing and smoking. Misuse and abuse can cause physiological changes to the vocal folds, creating vocal nodules, polyps, contact ulcers and edema. In the case of yelling, the vocal folds come together in a hard way. As they bang together again and again, swelling can occur, and eventually a blister can form.When the vocal folds are swollen or have a nodule/polyp, they can't come together as closely as they normally do. There is a chink or hole through which the air from the lungs can whistle through. The vocal folds vibrate in an irregular fashion. The result is a hoarse sounding voice.

Therapy for functional disorders involves identifying abuses and misuses and reducing or eliminating them. Individuals sometimes need help "finding" their old voice if the disorder has been longstanding. It is important to rule out an organic basis before starting voice therapy. A referral to an ENT (ear, nose, and throat doctor/otolaryngologist) is necessary to rule out an organic voice disorder.