Applied Linguistics 2013: 1–24 ß Oxford University Press 2013 doi:10.1093/applin/amt030 Involvement in University Classroom Discourse: Register Variation and 5 Interactivity FEDERICA BARBIERI Department of English Language and Literature, Swansea University, Swansea SA2 8PP, UK E-mail: f.barbieri@swansea.ac.uk 10 Research on the linguistic characteristics of university classroom discourse high- lights the salience, in this register, of non-informational and subjective aspects of discourse. This dimension of classroom discourse, however, has not been studied systematically. Taking a corpus-based approach, this study investigates the non- informational dimension of classroom discourse, focusing on the marking of emo- 15 tions, affect, and the speaker’s ‘involvement’ (Chafe 1982) in the talk of university professors, in a large corpus of American university classroom discourse. It tracks the use of involvement markers across class sessions representing three situational factors that define the university setting: academic discipline, level of instruction, and class size. Surprisingly, these factors have relatively little influence on in- 20 volvement in language, suggesting that involvement is pervasive in American classroom talk. However, involvement tends to be more common in small courses in the Humanities and Social Sciences, at the upper division and graduate level— courses that generally favor student participation, hence interactivity in discourse. Analyses of the relationship between involvement and interactivity reveal that 25 while interactivity tends to predict involvement, involvement is not limited to interactive discourse. INTRODUCTION Classroom discourse has been studied from a variety of research paradigms and methodological approaches, including the ethnography of communication, 30 conversation analysis, systemic functional linguistics, and text linguistics. The Applied Linguistics 2002 special issue (Zuengler and Mori 2002) illustrates micro-analytic approaches to the first three of these research traditions. Studies of the linguistic characteristics of classroom discourse typically take a text lin- guistics perspective, and essentially continue the tradition of descriptive studies 35 situated in English for Specific/Academic Purposes. Motivated by the chal- lenges faced by language learners during lecture comprehension, early studies in this tradition investigated the discourse organization of academic lectures (Young 1994), textual markers of discourse structure and organization (DeCarrico and Nattinger 1988; Thompson 2003), and the impact of discourse 40 markers on lecture comprehension (Chaudron and Richards 1986; Flowerdew