The present study explores the learnability of complex morphological patterns, specifically number and gender categories. The typology of morphological systems suggests that infrequent, complex, and structurally marked categories such as the dual are more likely to show neutralization or syncretism than unmarked categories. In two artificial language learning experiments, adult English speakers were exposed to a language with noun class categories both for gender and number. Results suggest that syncretism of gender across dual forms allows for greater learnability of the dual form. However, overall learnability was not affected by whether syncretism occurred in the singular, dual, or plural. These results further the understanding of the cognitive mechanisms that shape complex morphological patterns.