This article explores the cyclic interplay of documentation and linguistic theory, focusing on the case study of Southern Seenku (Gbene Ku) verbal morphology. Southern Seenku is a hitherto undocumented Mande language of Burkina Faso. Preliminary fieldwork on the language revealed that all verbs have two stem forms, each used in a variety of constructions. It was hypothesized that this division is based on an irrealis/realis distinction. Theoretical predictions of where realis and irrealis forms should be found were tested in subsequent fieldwork, and it is shown that the results of this fieldwork uphold the original analysis. The chapter concludes by considering how the Seenku data patterns fit into the broader context of Mande verbal morphology and the typology of (ir)realis.