Comparative literature is an academic field dealing with the study of literature and cultural expression across linguistic, national, and disciplinary boundaries. Comparative literature "performs a role similar to that of the study of international relations, but works with languages and artistic traditions, so as to understand cultures 'from the inside'". While most frequently practiced with works of different languages, comparative literature may also be performed on works of the same language if the works originate from different nations or cultures among which that language is spoken. The characteristically intercultural and transnational field of comparative literature concerns itself with the relation between literature, broadly defined, and other spheres of human activity, including history, politics, philosophy, art, and science. Unlike other forms of literary study, comparative literature places its emphasis on the interdisciplinary analysis of social and cultural production within the "economy, political dynamics, cultural movements, historical shifts, religious differences, the urban environment, international relations, public policy, and the sciences".