Patients with advanced lung cancer cannot speak at once, which may be caused by the tumor compressing the recurrent laryngeal nerve or the brain metastasis infringing the speech center of the brain. If patients with advanced lung cancer have mediastinal lymph node metastasis, the enlarged lymph nodes can compress or invade the recurrent laryngeal nerve, and when the recurrent laryngeal nerve becomes abnormal, the patients will suffer from dysphonia, dyspnea and other symptoms. If brain metastasis occurs in patients with advanced lung cancer and the metastatic tumors infringe on the speech center of the brain, they will also be unable to speak. In addition, patients with advanced lung cancer will also have inability to speak because of extreme physical weakness. Chest CT, cranial magnetic resonance and other examinations can be perfected to clarify the cause. It is recommended that advanced lung cancer patients with this symptom should go to oncology department of regular hospital for further consultation.