After a brief discussion of the concepts underlying the design of a high school district's composition program that emphasizes teacher inservice preparation and writing as process rather than product, this paper develops a theory of learning language skills similar to that used in learning a second language. A distinction is drawn between language acquisition as a natural, holistic, unconscious process and language learning as an extensive, carefully planned process implementing rules, algorithms, paradigms, and programmed exercises. The classroom is described as both a workshop where composition skills are acquired through prewriting, writing, and rewriting and as a laboratory where editing skills are learned. A modified version of Stephen Krashen's monitor theory of second language acquisition is discussed as well as its application in an ongoing study of freshman composition students at the University of Southern California. (AEA)