This chapter takes a historical-institutionalist approach to language politics, focusing on the language shift from a Tai-Kadai language to Indo-Aryan Assamese in the precolonial Ahom kingdom of Northeastern India. This unusual language shift involves those in power abandoning their language in preference of another, rather than subordinates doing so; the concepts of state tradition and language regime are used to analyze how and why this occurred. The chapter exposes the implicit assumptions about language and power in existing research and problematizes a rigid, genealogical classification of languages.