how they communicate each other?

If you want to stay in Perth for quite long time you must know how do they communicate each other, so they wont say that you're wierd bacause using to formal or informal languages.

Photo from http://www.melville.wa.edu.au

Every country had their each style to communicate and languages, so there are many different style to communicate between Indonesian students and Australian students that I know of. The Indonesian student that I know they like to use slang languages as the main language for communicate with the other teenagers today, just the same like mostly Melville student that I know they likely to use slang to talk with another students.

Students in Australia mostly use an informal languages even to communicate with the older people, they likely just call their name without using Ms, Mr, or Mrs, it's different to Indonesian students mostly they call someone older by their title, such like Ibu, Bapak to show their respect to the older people.

Even to their parents most of Australian students just call their parents name, it's going to be not very well mannered to call parents with their name.