English, the official language
Throughout the entire country, English is the official language spoken everywhere and by everyone. The Australian accent is rather special. Some syllables are stuck together and sometimes you might feel as though you haven't understood half of the words and sentences. A little adjustment time is necessary in order to understand everything well.
For example, the "i" sound is pronounced more like "oï" than "aï" and the "a" sound is often more drawn out than it should be, pronounced as "aaaa...". The letters "d", "g" and "t" are not pronounced at the end of words. For example, "liking" becomes "likin" or "first" is pronounced as "firs". Similarly, "you" is pronounced as "ya". But it's even more disconcerting when words are bundled together. It can be hard to figure out that "gimme" means "give me", that "dunno" actually means "I don't know" or that "emma chisit" means "how much is it".