This document outlines Communication Accommodation Theory (CAT), which proposes that in conversations, people will accommodate their language, speech patterns, and nonverbal behaviors to be more similar to or different from their conversation partners. It discusses four main assumptions of CAT: 1) similarities and differences in experiences affect accommodation, 2) perception and evaluation determine accommodation, 3) language conveys social status, and 4) accommodation has norms of appropriateness. The document also defines convergence, divergence, and overaccommodation, and discusses the scope and criticisms of CAT.