The basic questions that a scholar interested in the study of language asks are concerned with language structure, acquisition, and change. William Labov is a linguist who has deeply influenced the linguistic scene in the past 60 years. It is to Labov's credit that he showed, backed by solid evidence, that the questions concerning language change, structure and acquisition cannot be answered satisfactorily without examining language in its social context. In his opinion, even though human beings are innately endowed with the ability to acquire languages, and even if it is possible that a substantial part of language structure is governed by their innate language faculty, it is also clear that languages are inherently variable and that several important aspects of structure are created in a social space by human groups. Labov has worked with the languages of communities living on the margins of society, communities that survive in the ghettos of United States (US) cities. He has shown how stigmatisation of their languages leads to the intensification of the process of their marginalisation in society. He has been highly proactive in the area of affirmative action. His contributions to the fields of education and justice are indeed significant. Labov has also examined the correlation between language and ideology. Labov's studies on the concept of vernacular speech are discussed in this article. Labov brought about a paradigm shift in the study of language. He showed new ways of analysing language variation and took the proposals made in Weinreich et al. (1968) to their logical end. His contributions to empirical methodology would guide the future course of linguistic inquiry for many more years. He made the study of language variation in its social context an integral part of understanding the structure of language; he is certainly the first one to show how to examine language change in progress, a task that scholars before him thought could never be undertaken. His contributions to the fields of education, justice and affirmative action, and to the study of the relationship between language and ideology, remain remarkable.