This paper, based on the theory of Systemic Functional Linguistics (Halliday, 1985, 1994; Halliday and Matthiessen, 2004); on Appraisal Theory (Martin, 2000; Martin and White, 2005; White, 2003, 2010), more specifically on the Engagement system; and on Hengeveld's (1988, 1989, 2004) perspective on modality, aims to discuss the use, by authors of masters and doctoral degrees in the field of linguistics, of modal forms stemming from the verb "can" and its derivatives in the construction of discursive strategies. This study analyzed a corpus of 40 theses and 40 dissertations produced between 2008 and 2011, collected from websites of Brazilian public and private universities. The findings reveal an absence of criteria in choosing the modality resource of the modal verb "can", indicating responsibility either on the part of the author of the text or of the authors cited by him, allowing for different meanings to emerge due to the verb's relation to other elements within the discourse and within the context.
modality; academic writing; systemic-functional linguistics
