A baby’s love of sticking out his tongue may be a normal physiological phenomenon, or it may be a result of poor brain development, and may be accompanied by mental retardation. Babies usually start to show the action of sticking out their tongues when they are 3 to 4 months old. This is a way for babies to explore the world and express their satisfaction after eating, and babies will also stick out their tongues when they try to communicate with others or express their emotions. With growth and development, this action can disappear slowly. Some babies, in addition to frequent tongue out, if accompanied by tongue movement is not sensitive, wide eyes, dull eyes, mental retardation, motor and language development is significantly behind children of the same age and gender and other manifestations, then it may be due to brain dysplasia, the need for timely medical treatment. Baby’s love of tongue may also be related to other causes (such as hypothyroidism), it is recommended to take your baby for regular medical checkups to assess whether your baby’s development is up to the normal standard, and if any abnormalities are found, they can be detected and treated as early as possible.