principles: (1) that linguistic evolution occurs through successive changes made to specific linguistic elements; and (2) that these changes each belong to a specific area, which they affect either wholly or partially. It then follows from these principles that dialects have no natural boundary, since at any geographical point a particular language is undergoing some change. At best, they are defined by "waves of innovation"—in other words, areas where some set of innovations converge and overlap. The "wave" concept is integral to Saussure's model of geographical linguistics—it describes the gradient manner in which dialects develop. Linguistic waves, according to Saussure, are influenced by two opposed forces: parochialism, which is the basic tendency of a population to preserve its language's traditions; and intercourse, in which communication between people of different areas necessitates the need for cross-language compromise and standardization. Intercourse can prevent dialectical fragmentation by suppressing linguistic innovations; it can also propagate innovations throughout an area encompassing different populations. Either way, the ultimate effect of intercourse is unification of languages. Saussure remarks that there is no barrier to intercourse where only gradual linguistic transitions occur. Having outlined this monoglot model of linguistic diversity, which illustrates that languages in any one area are undergoing perpetual and nonuniform variation, Saussure turns to languages developing in two separate areas. In the case of segregated development, Saussure draws a distinction between cases of contact and cases of isolation. In the latter, commonalities may initially exist, but any new features developed will not be propagated between the two languages. Nevertheless, differentiation will continue in each area, leading to the formation of distinct linguistic branches within a particular family. The relations characterizing languages in contact are in stark contrast to the relations of languages in isolation. Here, commonalities and differences continually propagate to one another—thus, even those languages that are not part of the same family will manage to develop common features. Criticism Editions There have been two translations into English, one by Wade Baskin (1959), and one by Roy Harris (1983). Saussure, Ferdinand de. Course in general linguistics. Eds. Charles Bally & Albert Sechehaye. Trans. Wade Baskin, subsequently edited by Perry Meisel & Haun Saussy. NY: Columbia University Press, 2011. Original: Course in general linguistics. Eds. Charles Bally & Albert Sechehaye. Trans. Wade Baskin. NY: The Philosophical Society, 1959 (reprint NY: McGraw-Hill, 1966) Saussure, Ferdinand de. Course in General Linguistics. Eds. Charles Bally & Albert Sechehaye.