The study of the ways culture shapes language and language shapes culture, particularly the intersection of language and systems of power such as race, gender, class, and age.
Example
In Hip-Hop culture there exist many particular instances of sociolinguistics. Interestingly, with the rise of social media, there seems to be new dances every year that are invented, and new terms that are coined along with them. Socila media helps spread the reach of these dances and terms to people not so familiar with the culture. Eventually some of these words are added to the dictionary and officailly become part of the english lanuage. One example is the word "bling" which is said to have been invented by Lil Wayne. Recently the new word and dance that have been popularized by football player Cam Newton is the "dab" which was initially started in the Atlanta Rap Scene. Today most people know of the dab, and probably can do it; thus showing how culture in the Atlanta Hip Hop scene has affected people all over the US, and these people are using terms such as "dab" which they may have never used had they never known about it.