Three-year-old children can not speak is a delay in language development, first of all, we must exclude hearing impairment, vocal motor dysfunction, intellectual development, but also with environmental factors, disease factors, as follows: 1, environmental factors: common causes are language environment and social environment problems, the process of language development of young children need to listen more, more practice, imitation, communication is very important, especially the current epidemic The presence of strict community isolation in areas where the epidemic is serious reduces the opportunities for face-to-face communication and play with children of the same age, or even none at all, which can seriously affect the development of the child’s language function. 2. Disease factors: The main manifestation of autistic children is language dysfunction, which must be diagnosed by going to a child health clinic for the appropriate tests. Some genetic metabolic diseases can also be associated with delayed language development, including familial natural late speech, which also requires assessment and appropriate tests, such as genetic tests, at a child health clinic. Regardless of the cause of the delay, early identification of the cause and early intervention are the only viable options.