Purpose: Individuals with mild aphasia often report significant disruption to their communication despite seemingly minor impairment. This study explored this phenomenon through examining conversations of a person with mild aphasia engaging in argumentation--a skill she felt had significantly deteriorated after her stroke. Method: A person with mild aphasia and her husband recorded 4 conversations involving topical issues. The discourse dynamics and lexical-grammatical content were analyzed using systemic functional linguistic (Halliday & Matthiessen, 2004) and conversation analysis (Sacks, Schegloff, & Jefferson, 1974) frameworks. Results: The couple demonstrated similarities in the types of conversational moves, but the language of the person with aphasia was more nonspecific and simplified, manifesting in difficulties developing a logical argument and responding to the partner's line of argument. In addition, the nonaphasic speaker recurrently overlapped the aphasic speaker in order to request clarification of particular points, highlighting the types of behaviors that can occur in this form of higher level language activity. Conclusion: The complex argument task and the multilevel and multi-approach analysis are useful tools for examining persons with mild aphasia, revealing aspects that are often overlooked in standard tests. Treatment could incorporate more complex notions such as evaluative language and the role of overlap in complex conversations. (Contains 1 table and 2 figures.)