A study examines the dynamics of cultural pluralism and language in the ethnic mobilization, and resulting dissolution, of the USSR. It first examines ethnic composition, dominant nationalities, language groups without separate nationalities, patterns of ethnic populations within nationalities, and the influence of this multiculturalism on language policy. A distinction is made between assimilation ("Russification") and appreciation of nationality and language rights combined with political loyalty to a supranational union ("Rossification"). These issues are examined: the relationship that evolved between the communist party and the national populist fronts; the long-standing conflict between the Russian imperial legacy and national identity; trends in national language preservation in the context of the Soviet educational system, including bilingual education and resistance to Russian-medium instruction; unanticipated effects of mass politicization on national loyalties; conflict between official lack of religion and national religious traditions; the role of military training and indoctrination in national resistance; and dissonance between centralized economic planning and national interest in environmental protection. The role of official language policy in the process of national/ethnic mobilization is discussed. Officially sanctioned Russian ethnocentrism is blamed for Soviet dissolution and intensified ethnic conflict. A 75-item bibliography is included. (MSE)