Slang is a very informal kind of vocabulary, used mostly in speech by people who know each other well. Examples
See you down at the boozer (pub)
OK, let’s shove off ( go)
He’s real prat (fool)
Slang expression are not usually written and would be considered out of place in formal kind of communication. Many English slang expressions relate to things that people feel strongly about (e.g sex, family, and emotional relationship, drink, drugs, conflict between social groups, work, physical, illness, death).
She’s got tits like ripe melons. (breast)
I spent the weekend at my gran’s . (grandmother’s)
I’ve got some sort of bugs (illness)
Shut your gobs (mouth)
Kill the wogs ( colored people)
Many slang expression are used by members of particular social and professional groups, and nearly all slang is used between people who know each other well or share the same social background. So it is usually a mistake for outside to try delibaretly to use slang. This can give the impression that they are claiming membership of a group that they do not belong to. There is also the danger that th slang may be out of date. It is best to wait untill one is really becoming accepted as part of a community; one will then start using their slang naturally and correctly along with the rest of their language.