Although there is consensus that collaboration refers to two or more learners working together to accomplish a task (Davin & Donato, [Davin, K., 2013]; Ohta, [Ohta, A., 2001]), debate remains about how to assess collaboration. Researchers have pursued two approaches to evaluate collaboration during peer interaction: rater judgments (e.g., Ahmadi & Sedeghi, 2016; Winke, [Winke, P., 2013]) and qualitative coding of interactional patterns (e.g., Galaczi, [Galaczi, E. D., 2008]; Storch, [Storch, N., 2002a]). Largely absent, however, has been any attempt to describe the linguistic features of collaboration. Therefore, the present study uses corpus linguistic techniques to identify the linguistic markers of collaborative and noncollaborative peer interactions. Students of English as a second language (N = 80) enrolled in an intensive English program carried out a paired oral test as part of the program's formative assessment procedures. Their interactions were audio-recorded and rated using an analytic rubric with three categories (collaboration, task completion, and style), and transcripts were analyzed for 146 linguistic features using the Biber Tagger (Biber, [Biber, D., 1988]). Linguistic features associated with high collaboration included first- and second-person pronouns, "wh"-questions, "that" deletion, and subordinate conjunctions, whereas low-collaboration interactions were characterized by nominal forms. The collaborative and noncollaborative functions served by these linguistic features are discussed.