There are three areas of rules which we should consider:
Sociocultural rules: Speakers from similar cultural backgrounds know how to speak to each
other in terms of how formal to be, what kind of language they can use, how loud to speak, or how close to stand to each other.
Turn-taking: In any conversation, decisions have to be taken about when each person should speak. This is ‘ turn-taking’, a term which refers to the way in which participants in conversation get their chance to speak. They do this by knowing how to signal verbally or visually that they want a turn or, conversely, by recognizing when the other speakers are signaling that they want to finish and are therefore giving them space to take a speaking turn
Rules for writing: writing has rules too, which we need to recognize and either follow or purposefully flout ( e.g. internet chat).