In the course of the last 15 years, sociolinguistics (or the sociology of language) has established itself as a academic subject in many countries. The discipline promises to be of benefit in solving practical problems in such areas as language planning and standardization, language policy, and language teaching and therapy. Both research projects and publications and university teaching programmes in sociolinguistics now span such a wide field that it is hardly possible even for the experts to review the whole scope of the subject. A number of specialist periodicals and introductions and...