This article examines data from Lao, a radically isolating Southwestern Tai language spoken in Laos, Thailand, and Cambodia, and asks how speakers of such a language might cope without case. Lao is like Mandarin, Thai, Vietnamese, and Riau Indonesian in exemplifying the extreme of pragmatically oriented grammar. Where case marking simply distinguishes who from whom, it is mostly dispensable, thanks to the richness of pragmatics. Moreover, for more ‘expressive’ functions of case marking, where features of transitivity are manipulated for expressive or information-structural effect, Lao finds constructional means to treat certain arguments in special ways, thereby explicitly marking non-redundant semantic information in case-like ways. This article also examines patterns of argument-predicate relations, focusing on monovalent predicates, symmetric and other non-oriented bivalent predicates, and asymmetric bivalent predicates. Finally, it considers the expressive functions which case marking might perform, that is where special treatment of one or another argument serves to manipulate semantic distinctions in the construal of event structure and participant involvement.