This course explores how the sounds, words, and grammar of languages change through time, and how to reconstruct languages of the past. There is a particular emphasis on applying the comparative method and principles of internal reconstruction, which allow us to uncover regular changes in a language's history, determine which languages developed from a common source, and reconstruct that original language. Other topics include how to propose language family trees (including recent computational models), and how unrelated languages influence each other. Strong focus on analyzing language data from many different parts of the world.