Sudden loss of voice can be caused by overuse of voice, acute laryngitis or paralysis of the vocal cords. 1. Excessive use of the voice: It may be due to excessive use of the voice, such as lecturing, or loud quarrels after the voice becomes mute, is due to the vocal cord congestion, swelling, or even serious cases of submucosal hemorrhage. 2. Acute laryngitis: caused by bacterial or viral infection, resulting in congestion of the laryngeal mucosa or congestion and swelling of the vocal cords, which can lead to a sudden mute voice or pain and phlegm at the same time. 3. Vocal cord paralysis: Some patients may also have the condition of vocal cord paralysis, one side of the vocal cords have poor movement or even complete paralysis, resulting in poor closure of the vocal cords, and sudden loss of voice mute situation. If the above symptoms occur, it is recommended to go to the hospital in time, early diagnosis and formal treatment.