Communication is fundamental to the human condition but is impaired in life-altering ways for more than 2.4 million individuals with aphasia in the United States. Individuals with aphasia identify discourse-level communication (i.e. language in use) as a high priority for treatment. The central premise of most aphasia treatments is that restoring language at the phoneme, word, and/or sentence level will generalize to discourse. However, treatment-related changes in discourse-level communication are modest, poorly understood, and vary greatly between individuals with aphasia. In response, this study conducted a multilevel discourse analysis of archival, monologic discourse outcomes across two high-intensity Semantic Feature Analysis clinical trials (combined n = 60). First, we evaluated improvement on theoretically motivated discourse outcomes representing lexical-semantic processing, lexical diversity, grammatical complexity, and discourse informativeness across study enrollment, entry, exit, and 1 month follow-up. Second, we examined the potential moderating role of non-language cognitive factors (semantic memory, divided attention, and executive function) on discourse outcomes in a subsample of participants (n = 44). The present study found no evidence for meaningful or statistically reliable improvements in monologue discourse performance after Semantic Feature Analysis. There was weak and inconsistent evidence that non-language cognitive factors may play a role in moderating treatment response. While improving discourse-level communication may help to reduce the profound communication and psychosocial consequences of aphasia, these findings indicate that intentional treatment design with a focus on generalization to discourse is likely necessary to meaningfully improve discourse-level communication in aphasia in both research and clinical practice. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]