Episodes in university classrooms: A corpus linguistic investigation

Over the past three decades, the linguistic characteristics of texts have been researched from two major perspectives: one focusing on the typical linguistic characteristics of texts and text types, and the other focusing on the internal discourse organization of texts. Studies of the first type have usually been quantitative, and in more recent years, they have been carried out on large text corpora using the techniques of corpus linguistics. Studies of the second type have usually been qualitative and based on detailed analysis of one or two individual texts. However, few studies have attempted to combine these two research perspectives.; This study reports on the findings of a corpus linguistic approach to analyze the episodic structures in one particular register: university classroom discourse. Episodes are defined as topically coherent and linguistically marked units of discourse. Episodes are extracted from lectures through automated means utilizing a modified version of the Vocabulary Management Profile (Youmans, 1991). In short, the VMP tracks the introduction of new vocabulary into a discourse. The peaks in the VMP, reflecting a dense introduction of new vocabulary, correspond to topical episodes; valleys in the VMP, reflecting a primary reliance on repeated vocabulary, mark transitional talk or commentary in between episodes. Once identified, episodes are analyzed with regard to a range of linguistic features. Applying cluster analytical techniques with those linguistic features, a taxonomy of episode types is developed. This taxonomy shows three major types of episodes exhibiting different linguistic characteristics: (a) Procedural episodes; (b) Content-focused episodes; and (c) Involved Narrative episodes. Using this framework the variation in which academic classrooms are constructed is investigated from three perspectives: by discipline, by level of instruction, and by degree of interactivity.