There are many causes of voice loss, the common ones include: 1) inflammatory infections, hoarseness after vocal fold congestion and edema; 2) benign lesions of the vocal folds: such as vocal fold polyps, vocal fold cysts, etc.; 3) hoarseness after viral infections causing neuritis; 4) laryngeal tumors invading the vocal folds, resulting in loss of voice; 5) laryngeal trauma causing dislocation of the cricoarytenoid joint or abnormal vocal fold activity; 6) abnormal vocal fold activity after compression of the vagus nerve or the recurrent laryngeal nerve by cervical or mediastinal masses, etc.