Challenging the position on the autonomy and homogeneity of the language system. Areas and branches of sociolinguistics. Dimensions of linguistic diversity: Geographical differentiation and dialects; social stratification and sociolinguistics; communication situations and functional varieties; coexistence – language contact and phenomena of social bilingualism, bilingualism and language shift. Pidgin languages, creoles and lingua francas. Majority and minority languages. Diversity and language change. Sociolinguistic inequality. The case of linguistic sexism. Sociolinguistic attitudes. Methodological issues of sociolinguistic research