The strategic and indirect use of language in academic discussions poses particular difficulties to non-native speakers of English. In order for English language teachers to address the needs of non-native speakers in this area, descriptions of how language is used by proficient speakers of English in academic discussions are required. This paper reports on the markers of detachment and commitment in speaking in discussions between proficient speakers of English in classes in a British university. Findings reported concern the linguistic devices used for marking detachment and commitment and their uses for specific interactional functions. These findings are explained in relation to the theoretical framework of politeness established by Brown and Levinson (1987). It is concluded that the native speakers in the discussions were expert in using markers of detachment and commitment to achieve precise interactive objectives. Students from non-English speaking backgrounds experience difficulties in attempts to achieve such objectives, and have trouble decoding such indirect uses of language. The contributions they make to discussions may come across as overly direct, abrupt, and critical. Thus, non-native speakers may need to be made sensitive to the conventional and indirect ways of interacting in discussions in English. (Contains 21 references.) (Author/KFT)