Yes, all of them. Everyone uses slang.
Because a) they think it's cool and b) it relates them to normal people
People use slang so that other people won't know what they're talking about.
Always. People started inventing slang as soon as they invented language.
It is a slang word for people, made famous by a Harry Enfield character.
100%. Everyone in the world uses slang.
It appears to me that the majority of Londoners use slang.
Australians do!
People have used slang since the dawn of time. There was slang every since cave men but it wasn't slang it was the pronounciation for thier words.
Slang changes with vocabulary and the times, much of it coming from the military of all countries
Writers use slang to make their writing more relatable and engaging to a specific audience. Slang can also add authenticity to dialogue or help establish a certain tone or setting within a story.
People usually curse to express strong emotion, mostly anger and frustration with a person, an object, or a circumstance. People use slang usually in order to fit in with a particular group. Slang is usually used in casual or humorous speech. It would not be appropriate to use slang in formal contexts such as in the business or professional world, at school, or in religious settings such as in church.