Two hypotheses regarding the distribution of emergent tense-aspect morphology in SLAhave been proposed: the aspect hypothesis, which claims the distribution of interlanguage verbalmorphology is determined by lexical aspectual class, and the discourse hypothesis, which claimsit is determined by narrative structure. Recent studies have tested and supported both hypothesesindividually. This study expands the investigation to include an analysis of both narrativestructure and lexical aspectual class in a single corpus comprising 74 narratives (37 oral andwritten pairs) produced by adult learners of English as a second language at various proficiencylevels. The results suggest that both hypotheses are necessary to account for the distribution ofverbal morphology in interlanguage.