Two and a half year old baby speech regression, consider is due to normal physiological development, psychological factors, developmental stuttering and other factors. 1. Normal physiological development: two and a half year old children’s thinking ability and language development is rapid, strong learning ability, if not adapted to a short period of time to more complex knowledge and methods of expression, it can be shown to speak intermittently or less talk, etc.; may also be because of the rapid development of the thinking ability, language development does not match the situation, appearing to speak logically and intermittently. 2. Psychological factors: Children at the age of two and a half have begun to have self-consciousness and psychological activities. When the external environment makes children feel uncomfortable, nervous or even anxious, it may lead to intermittent, illogical, little or no speech. 3. Developmental stuttering: Several studies have shown that there is a genetic factor in developmental stuttering. Children with a family history of stuttering are more likely to suffer from developmental stuttering and to have stuttering and interrupted speech. Children at the age of two and a half are in the critical period of language development. Most of the sudden regression in children’s speech is due to normal physiological development and psychological factors. Parents should be patient in teaching children so that they can have a good environment for language learning and expression, and consult a doctor to rule out pathological factors if necessary.