The timbre of the beloved Crocodile Hunter, one of the sexiest accents in the world, and the diction in which Russell Crowe yells at everyone, is actually just the result of lots of drinking. That makes a lot of sense, given Steve Irwin's one-time antics and ol' Russell's anger issues -- but it's seriously the reason Aussies sound the way they do.
According to Dean Frenkel, a lecturer at Victoria University, the Australian accent was passed down by inebriated forefathers who added a slur to the Queen's English. Historically, the Australian language was influenced by English, Irish, Aboriginal, and German. But, apparently, no single factor influenced their speech patterns quite so much as how often and heavily these settlers drank, bringing out that unique twang the world now knows and loves. And if you've ever been in a hostel, you'd recognize that speech pattern and drinking, as it must be a law that every hostel contain an Australian who's been drinking.
Frenkel writes in his article for The Age, "For the past two centuries, from generation to generation, drunken Aussie-speak continues to be taught by sober parents to their children." Which definitely explains that degree of laziness to the accent. The t's, I's, and s's are taken out of words, and certain nouns are pronounced without annunciation. As an example, the article cites the pronunciation of "night" as "noight."