Once speech educators turn their attention to the "ideational" function of oral language--that portion pertaining to thinking--rather than the relational function, they will see that speech can and should be incorporated into every discipline. The psychologist Lev S. Vygotsky envisions the ways in which humans use speech to reorder their thinking as a series of stages in which emotional and communicative functions of speech are expanded by the addition of the planning function. Aside from the need for a variety of speaking experiences to enhance language and thought development, group discussion enhances what Vygotsky calls the "zone of proximal development," or the innate capacity that each individual possesses at any one time. Thus, enhancing language experience becomes the best way of teaching even the higher levels of thinking. According to Piaget's theories, adolescence may be the best time for such oral communication in the classroom. At around the age of 14, students begin the transition from ego-centrism to socio-centrism, a condition necessary for higher abstract thought. (HTH)