Intended for teachers, this booklet shows how spoken language can affect student thinking and presents strategies for teaching critical thinking skills. The first section discusses the theoretical and research bases for promoting critical thinking through speech, defines critical thinking, explores critical thinking as abstract thinking, and tells how speech activities such as drama and discussion promote abstract thinking. The second section explains the structure and dynamics of small-group discussion, explores three specific thinking skills (reasoning, predicting, and projecting), and describes exercises designed to develop each skill. (EL)