This language unit for grade 10 builds on a definition of the expository use of language developed in the two previous 10th-grade units. In a brief overview of report language, the referential language of Thomas Huxley is compared with the expressive language of Edgar Allan Poe. The writings of S. I. Hayakawa, Hans Guth, and others are examined for and understanding of the language of reports. The two major topics of the unit are (1) the organization of expository discourse--the effective use of introductions and conclusions, and the unity, emphasis, and coherence of the body; and (2) the modes of exposition--description, illustration, comparison and contrast, classification, causality, and definition. Included are sample lectures, inductive questions, a bibliography on expository writing and speaking, worksheets, and writing-speaking assignment sheets which can be integrated with other units of the curriculum. (See TE 001 328 for the introductory unit on discourse.) (JB)