Sociolinguistics is the descriptive study of the effect of any and all aspects of society, including cultural norms, expectations, and context, on the way language is used, and the effects of language use on society. Sociolinguistics differs from sociology of language in that the focus of sociolinguistics is the effect of the society on the language, while the latter's focus is on the language's effect on the society. Sociolinguistics overlaps to a considerable degree with pragmatics. It is historically closely related to linguistic anthropology and the distinction between the two fields has even been questioned recently. It also studies how language varieties differ between groups separated by certain social variables, e.g., ethnicity, religion, status, gender, level of education, age, etc., and how creation and adherence to these rules is used to categorize individuals in social or socioeconomic classes. As the usage of a language varies from place to place, language usage also varies among social classes, and it is these sociolects that sociolinguistics studies. The social aspects of language were in the modern sense first studied by Indian and Japanese linguists in the 1930s, and also by Gauchat in Switzerland in the early 1900s, but none received much attention in the West until much later. The study of the social motivation of language change, on the other hand, has its foundation in the wave model of the late 19th century. The first attested use of the term sociolinguistics was by Thomas Callan Hodson in the title of a 1939 paper. Sociolinguistics in the West first appeared in the 1960s and was pioneered by linguists such as William Labov in the US and Basil Bernstein in the UK. For example, a sociolinguist might determine through study of social attitudes that a particular vernacular would not be considered appropriate language use in a business or professional setting. Sociolinguists might also study the grammar, phonetics, vocabulary, and other aspects of this sociolect much as dialectologists would study the same for a regional dialect. The study of language variation is concerned with social constraints determining language in its contextual environment. Code- switching is the term given to the use of different varieties of language in different social situations. William Labov is often regarded as the founder of the study of sociolinguistics. He is especially noted for introducing the quantitative study of language variation and change, making the sociology of language into a scientific discipline.