The emerging literature that combines economics and linguistics has demonstrated that linguistic factors affect economic decisions and also suggested ways in which economic forces affect language phenomena. This two-way interaction makes the economics of language a rich area of study. The present chapter explores what we can learn from economic models of language dynamics, particularly concerning the survival and extinction of languages. From the perspective of economics, the phenomenon of language death is unsurprising: network externalities and strategic complementarities provide strong incentives to teach, learn, and use majority rather than minority languages. Yet some minority languages are still thriving. The economic literature offers some explanations based on choices about language use, language acquisition by adults, language transmission across generations, and migration between linguistic regions. Economists and linguists have also explored how economic forces may have influenced language birth and death over the very long run. While the chapter focuses on economic models—which are distinguished by optimizing decisions—researchers from the fields of mathematics, computer science, physics, and biology (as well as, of course, linguistics) have explored related questions. The chapter briefly discusses these contributions and notes some examples of independent discovery from different disciplines, suggesting there is scope for productive interdisciplinary research.