Non-periodic vibrations of the vocal folds manifest clinically as hoarseness (Hoarseness), the most frequently occurring voice problem. It can be caused by the thickening and increased stiffness of the vocal folds due to different reasons and the increase in the fissure of the closing phase vocal folds. The corresponding rough sound, breath sound, whispering sound or even complete loss of voice occurs depending on the lesion. The common causes of hoarseness are as follows: 1, congenital dysphonia: hoarseness caused by laryngeal webbing, vocal fold dysplasia (vocal fold groove), arytenoid cartilage displacement, etc. appears after birth. 2, inflammation: acute inflammation has an acute onset, the lighter the voice is rough, pronunciation effort, serious due to more secretions and sticky larynx, vocal fold congestion and swelling, poor closure of the vocal folds, hoarseness is obvious, can appear loss of voice, and accompanied by the symptoms of general discomfort. In laryngeal diphtheria, the mucous membrane is swollen with white film formation and hoarseness and weakness of pronunciation. Chronic inflammation develops slowly, initially intermittently, with hoarseness aggravated by excessive use of voice, and then gradually develops into persistent hoarseness. Due to the specific reflux pharyngitis caused by dysphonia, in addition to hoarseness, it is often accompanied by foreign body sensation in the pharynx, more mucous sputum, and often sore throat. 3. Pronunciation abuse: chronic mechanical injury, vocal fold abrasion, epithelial thickening due to improper use of voice. It can be seen in vocal cord nodules, vocal cord polyps, edema of Renk’s layer, etc. The degree of hoarseness is related to the location and size of the lesion. 4, tumor: benign tumor hoarseness develops slowly, while malignant tumor hoarseness can be progressively aggravated in a short period of time, and finally complete loss of voice. 5, trauma: various causes of trauma, foreign bodies, surgery and other causes of local scar formation. Vocal cord paralysis: Vocal cord paralysis caused by various causes of central nervous system, peripheral nervous system or myogenic disorders can cause varying degrees of hoarseness. The severity of symptoms is determined by the location of the paralyzed vocal cords and the degree of compensation of laryngeal function. Bilateral paralysis of the superior laryngeal nerve can be accompanied by choking caused by accidental aspiration of food and saliva into the respiratory tract; unilateral paralysis of the recurrent laryngeal nerve shows varying degrees of incomplete closure of the vocal folds, hoarseness and fatigue, accompanied by misaspiration or breath sounds, but can be asymptomatic after compensation by the opposite side. The paralysis of both recurrent laryngeal nerves causes vocal fold paralysis, both vocal folds are fixed in the middle position, the articulation is hoarse and weak, and cannot be sustained, whispering sound and breathing difficulty of different degrees may appear. The damage to the vagus nerve not only destroys the motor nerve of the larynx, but also loses innervation of the pharyngeal muscle. The destruction of sensory information originates from the receptors of the larynx, trachea, pharynx and lung. Vagus nerve injury due to neck surgery is often accompanied by symptoms of other cranial nerve injuries. 7. Hysterical hoarseness: the larynx itself is normal, with more sudden onset of hoarseness, varying in degree from whispering to complete loss of voice, but normal coughing, crying and laughing. Hoarseness recovers quickly and can recur. 8.Other: Due to changes in age, gender and hormone level, hoarseness can occur in different degrees during the voice change period, female menstruation period and old age stage.