The baby is two and a half years old and can not speak may be related to speech delay, short tongue tie, hearing impairment, etc., can be treated through speech training, surgical treatment, wearing hearing aids and other methods. 1. Delayed language development: If a two-and-a-half-year-old baby can call mom and dad but can’t say short sentences, it may be caused by the baby’s delayed language development. At this time, parents can teach their babies to speak by often talking to them and letting them follow the repetitive language training. 2. Short tongue tie: It is a kind of congenital developmental abnormality, which will affect the baby’s eating and pronunciation, thus causing the baby to be unable to speak. It can be treated by surgery such as tongue tie incision or tongue tie lengthening under professional doctor’s advice. 3. Hearing impairment: If the baby has hearing impairment, there is no way to hear the sound, so he/she cannot speak and pronounce normally, resulting in the baby not being able to speak. Parents should take their babies to regular hospitals for hearing tests to clarify the cause of the disease, after which the baby can be treated by wearing hearing aids and other methods. When the baby is two and a half years old and still can’t speak, you should take the baby to the doctor in time, under the guidance of professional doctors to clarify the cause of the disease and carry out treatment.