The phenomenon of retroflexion is discussed, and its occurrence in about 150 selected languages is examined from a geographical and a diachronic point of view. The clustering of such languages into distinct areas has been explained through the postulation of a hypothesis regarding their development in language. After a detailed examination of four different areas of retroflexion, their known history, and the present position of retroflexion in them, an attempt is made to generalize the environments that induce retroflexion in a given sound, and also to postulate developmental tendencies. Lastly, the place of retroflexion is a system of phonics is explained. (Author/AM)