There are many reasons why four-year-old children do not speak clearly, to rule out the lack of language training first, generally active exercise speech, speech after the symptoms can be improved. If this possibility is ruled out, pathological factors should be considered. The more common causes are bad hearing, intellectual developmental disorders, and structural malformations of the oral pharynx, and it is recommended that the child be promptly taken to the doctor for examination and then targeted treatment.1. Bad hearing: partly caused by bad hearing, it is recommended that the hearing test be perfected at the ENT department. If the hearing is moderate or above decline, it will lead to delayed speech development, slurred speech and poor directional discrimination. In the case of severe deafness, the child will miss the peak of speech development and will be congenitally deaf because of the inability to receive external sound stimulation. It is recommended to conduct brainstem evoked potentials, otoscopy, multi-frequency steady-state auditory evoked responses, temporal bone CT and other auxiliary examinations to help doctors clarify the cause and degree of hearing loss, some children need to wear hearing aids to improve their hearing, and some need to cooperate with doctors to do cochlear implantation. The common manifestations are slow speech development, communication disorder, poor self-care ability, etc. It is recommended to go to the pediatric department and improve the mental development scale test and head MRI examination under the guidance of the doctor. Mental retardation can make it difficult for the child to receive adult education, and intellectual rehabilitation training can be conducted. 3. Structural deformities of the oral pharynx and larynx: such as congenital hypertelorism, short tongue ligament, congenital cleft lip and palate, vocal cord deformity and other structural deformities of the oral pharynx and larynx can also lead to this condition, and it is recommended to go to the Department of Otolaryngology and Stomatology to improve electronic nasopharyngoscopy and oral examination. The above structural deformities can lead to difficulty in pronunciation and slurred pronunciation, and can also cause low self-esteem in children, who are afraid to open their mouths and also cause slurred speech. Many patients can choose to follow the medical prescription for surgery, and rehabilitation training is needed after surgery.