This seminar will focus on cross-linguistic variation in differential argument marking (DAM): case patterns determined by an argument's semantic properties (e.g., specificity, animacy, etc.). In addition to relatively well-known differential object marking (DOM) patterns where the accusative case of an object is determined by its interpretation, we will also explore other, lesser-known DAM patterns involving the case and/or interpretation of the subject. Through the lens of DAM, we will investigate the relationship between the case and interpretation of arguments, and its implications for theories of case assignment, the nature of case features, and the definitions of cases such as accusative and ergative.