If an infant sticks his tongue out frequently, the following causes are mainly considered: 1. The child’s micturition period, when the child is in the micturition period at 2-3 months of age, will often show the symptoms of tongue out, which is a reaction of the child’s perception of the world, there is no need to worry. 2. 3. Symptoms caused by mental disorders, such as congenital dysfunction or congenital hypothyroidism, children tend to stick out their tongues all the time, and their development is often backward at this time.