Sociolinguistics
Indian and Japanese linguists first studied the social parts of language in the 1930s. Louis Gauchat in Switzerland also studied this in the early 1900s. However, none of them were known in the West until much later. The study of why language changes started during the late 1900's in the wave model. Thomas Callan Hodson was the first person to us the word sociolinguistics. It was in an article he wrote in 1939 called "Sociolinguistics in India". This was printed in a magazine called Man in India. Sociolinguistics in the West first came in the 1960s. It was pushed forward by linguists such as William Labov (in the US) and Basil Bernstein (in the UK). In the 1960s, William Stewart and Heinz Kloss introduced the simple ideas for the concept of pluricentric languages. This explains how standard language varieties are different between countries (e.g. American/British/Canadian/Australian English; Austrian/German/Swiss German; Bosnian/Croatian/Montenegrin/Serbian Serbo-Croatian).