The reasons why a 3-year-old child’s speech is incomprehensible to others may include abnormalities in the articulation system, abnormalities in the auditory system, and abnormalities in the development of brain functions. 1. Abnormalities in the articulation system: a short tongue tie or cleft lip and palate can cause children to have slurred speech, which should be examined by the Pentacenter and treated surgically. 2. Abnormalities in the auditory system: children with hearing impairment are unable to hear others clearly, which leads to their own speech being unintelligible to others. 3. Abnormal development of brain function: children themselves have intellectual problems, can’t understand other people’s speech well, can’t imitate other people’s speech, which will also be manifested in unclear speech, and may also have delayed intellectual and behavioral development. 3-year-old children speak, there may also be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.