This volume presents the long-anticipated results of several decades of inquiry into the social origins and social motivation of linguistic change.Written by one of the founders of modern sociolinguisticsFeatures the first complete report on the Philadelphia project designed to establish the social location of the leaders of linguistic changeIncludes chapters on social class, neighborhood, ethnicity, gender, and social networks that delineate the leaders of linguistic change as women of the upper working class with a high density of interaction within their neighborhoods and a high proportion of weak ties outside of it