In this article, we consider the theoretical debates and frameworks that have shaped research on language development and intervention in persons with mental retardation over the past four decades. Our starting point is the nativist theory, which has been espoused most forcefully by Chomsky. We also consider more recent alternatives to the nativist approach, including the social-interactionist and emergentist approaches, which have been developed largely within the field of child language research. We also consider the implications for language development and intervention of the genetic syndrome-based approach to behavioral research advocated by Dykens and others. We briefly review the impact and status of the debates spurred by the nativist approach in research on the course of language development in individuals with mental retardation. In addition, we characterize some of the achievements in language intervention that have been made possible by the debates spurred by nativism and the various alternatives to it. The evidence we consider provides support for all three alternatives to the nativist approach. Moreover, successful interventions appear to embody elements of several of these approaches as well as other theoretical approaches (e.g., behaviorism). We conclude that language intervention must be theoretically eclectic in its approach, with different strategies appropriate for teaching different features of language, at different points in development, and for children displaying different characteristics or learning histories.