The purpose of this study is twofold: to explore the social and linguistic factors that influence the variable application of some phonological processes of Central Asturian, and to test the hypothesis that establishes a relation between the structure of society and the hierarchical structure of phonological segments. This hypothesis predicts that processes that operate at a higher level in the segmental structure will be socially less acceptable than processes that affect the segmental structure at a lower level. Chapter one outlines the socio-historical circumstances that have led to the present linguistic situation of Asturias. It describes the origins of Asturian and Castilian, the two languages in contact in the area, and the relation between these languages up to the present day. The most representative characteristics of the pronunciation of Central Asturian are also presented in this chapter. In chapter two, the treatment of post-nuclear stop and nasal segments, and the processes that affect stressed and unstressed vowels in Asturian, are interpreted within the theoretical framework provided by autosegmental phonology. The processes that affect stop segments are viewed as processes triggered by sonority restrictions of the Asturian syllable. All processes operate on a structure in which segmental features are hierarchically organized by delinking and spreading features, plus some language-specific default rules. The third chapter presents the results of a sociolinguistic study conducted in the industrial city of Langreo, in Central Asturias. This study employs the methodology developed in quantitative sociolinguistic studies. Speech data from the city of Langreo were obtained in a series of recorded interviews conducted by the author with a representative sample of residents. The results of the variational analysis determine the actual degree of use of Asturian features among the different sectors of the population, and address questions of the status and stability of the local language. The results partially support the hypothesis that there is a relation between the segmental structure and the structure of society.