In the 200 odd years since settlement, Australian English and British English have drifted apart. Words that met an untimely death in the old country have remained alive in Oz. New words have been invented. I'll stick to words and phrases that are so deeply entrenched that I have to remind myself that my British and North American friends might not understand what I'm saying. I hasten to add that I was born in the UK and retain some memory of how English was spoken in that country.
Ocker: vulgar speech: sometimes faked by middle-class Australians pretending to come from working-class backgrounds: developed to perfection by former Australian Prime Minister, Bob Hawke. Based on Oscar, a vulgar little larrikin in a 1960s TV series.
Larrikin: boisterous, often badly behaved young man. 19th century English dialect.
Galah: Stupid person. After the rosy cockatoo, famed for hanging upside down in the rain.
Tucker: food. From early 19th century British slang.
Mate: Used by people trying to be friendly and people with a bad memory for names.
Thongs: sandals, flip-flops. Not to be confused with the North American "G-string".
Wowser: censorious person. Used of killjoys trying to stop you having a good time.
Dunny: toilet. From Scottish dialect.
Thunder box: toilet.
Poor bastard: term of affection.
Clever bastard: term of abuse.
Bloody: very.
Mob: crowd. Used for both animals and people.
Wog: minor infection.
Hoon: lout, especially one who drives dangerously.
Dinkum: genuine, true, honest.
Sheila: girl or woman. From Irish form of Celia.
Crook: unwell.
Shonky: unreliable, dishonest.
Spiel: story. From German.
Wag: play truant.
True blue: worthy, genuine.
Bitumen: tarmac. Refers to sealed roads as opposed to dirt roads.
Creek: intermittent watercourse, usually steep-sided. Differs from American and British usage.
Billabong: water hole, particularly in a dry riverbed. Aboriginal.
Property/station: large farm or ranch. The British term "farm" didn't seem appropriate for the huge holdings allotted to early settlers.
Grazier: Someone who farms sheep or cattle.
She'll be right: Don't worry.
Good on yer: thanks.
Avag'day: goodbye.
Goodbye: God be with you. No longer used in that sense.
Gorblimey: struth. From "God blind me." Not much used anymore.
Wotcha: hullo. From "What hails you?" Not much used anymore.
Translate the following: A mate of mine (whose name I can't remember) had this spiel about a young larrikin who stole the school bus and went hooning with a mob of young sheilas. They wagged off down to the creek where he tried to impress the girls by burning rubber. The stupid galah was wearing thongs and got one stuck under the pedal. He lost control. The bus left the bitumen. He swerved to avoid a mob of cattle and ended up in a billabong. The grazier, who was droving the beasts, jumped in to rescue the kids. The poor bastard got a wog from the dirty water and he's now so crook he's confined to the station and spends half his time in the dunny.