Slag can be used to communicate like though talking on a phone or a text or speaking to someone face to face but there are sometimes you don’t use it to maybe mark a form a respect.
This maybe because the people who bought you up did not teach you to talk in that way like some people may say you wasent born on the streets. Also you are told that when you go for a job you are not going to use that type of word structures to try and get someone to give you a job