Delayed language development is manifested by the fact that the child’s ability to express and understand language is significantly lower than that of children of the same age and gender. 1. After the age of speaking, they still cannot speak. Or persistently have difficulty in speaking or cannot speak. 2. After being able to speak, the ability to speak progresses slower than children of the same age. 3. Can speak, but lacks language organization and skills. 4. Vocabulary, grammar and other language skills are significantly lower than those of normal children of the same age. 5. Slow to respond, slow to react and slow to reply to others’ questions. 6. Significant language difficulties or difficulty in understanding parental instructions. There are individual differences between different children, and the specific performance also has some differences. Failure to intervene in a timely manner can lead to emotional and psychological abnormalities, affecting physical and mental health. Once the above symptoms appear, it is recommended to consult a doctor to confirm the diagnosis. According to the results of the examination, follow the doctor’s instructions for treatment.