The document discusses different approaches to language description that are relevant to English for Specific Purposes (ESP). It outlines classical/traditional grammar, structural linguistics, transformational generative grammar, language variation and register analysis, functional/notional grammar, and discourse/rhetorical analysis. For each approach, it provides information on developers, interests, and how the approach describes language. The conclusion emphasizes that communication has structural, functional, and discoursal levels that complement each other, and distinguishes between performance and competence.