Speech community

Speech community is a concept in sociolinguistics that describes a more or less discrete group of people who use language in a unique and mutually accepted way among themselves.Speech communities can be members of a profession with a specialized jargon, distinct social groups like high school students or hip hop fans (see f.eg. ghetto lingo), or even tight-knit groups like families and friends. In addition, online and other mediated communities, such as many internet forums, often constitute speech communities. Members of speech communities will often develop slang or jargon  to serve the group's special purposes and priorities.
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Noun
1. people sharing a given language or dialect
(hypernym) community