The document discusses key concepts in analyzing text as discourse including definitions of text and discourse, and how texts make up discourse. It also covers functional categories and styles used in discourse analysis, such as modality, cohesion, transitivity, and discourse presentation. Modality refers to how opinions are expressed, and there are four types: epistemic, perception, deontic, and boulomic. Cohesion provides textual ties between units. Transitivity encodes meanings in clauses. Discourse presentation analyzes speech and thought representation with categories like direct and indirect speech.