Sociolinguistics is a term including the aspects of linguistics applied toward the connections between language and society, and the way we use it in different social situations. 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.
Slang only uses in particular occasion and particular group. Sometimes, only the particular group who knows or understands about language variation which they will use slang if there is the same understanding about the word they use. Slang can be specific communicating in particular special group.
Slang terms are often known only within a clique or ingroup. For example, Leet (“Leetspeak” or “1337″) was originally popular only among certain Internet subcultures, such as crackers and online video gamers. During the 1990s, and into the early 21st century, however, Leet became increasingly more commonplace on the Internet, and it has spread outside Internet-based communication and into spoken languages. Other types of slang include SMS language used on mobile phones, and “chatspeak,” (e.g., “LOL”, an acronym meaning “laughing out loud” or “laugh out loud” or ROFL, “rolling on the floor laughing”), which is widely used in instant messaging on the Internet.