According to Freud, a stage from birth to age 12 to 18 months, in which an infant’s center of pleasure is the mouth, is called oral stage.
According to Freud oral stage is the first stage in an infant's life when he is mainly concerned with the pleasure he receives from his mouth and its functions. As with all Freud's stages , excessive frustration or satisfaction may leave a person fixated on it, with the eventual result that, in this case, as an adult he may exhibit an oral character typified by a great need for oral stimulation in the form of food, drink, cigarettes or even talking-especially perhaps when making biting comments.