There are many reasons why you can’t make a sound when you speak, including vocal cord paralysis, acute laryngitis, and mental stress. 1. Vocal cord paralysis: when the laryngeal nerve is damaged, it will cause damage to the vocal cords, which will lead to the inability to speak. 2. Acute laryngitis: Acute laryngitis can be caused by bacterial or viral infections, which can lead to incomplete closure of the vocal folds, edema of the vocal folds on both sides, and other symptoms, and thus can cause the inability to speak. 3. Mental stress: when suffering from major mental stimulation, the cerebral cortex on the regulation of the sound-constituent tissue malfunction, can lead to a transient speech disorder. It is recommended that the patient go to a professional hospital for examination to identify the cause of the disease and follow the doctor’s instructions for treatment.