What? You're American. You speak "English". Don't Australians do the same? Sort of.
When our son went off to Townsville as an exchange student at James Cook University, we got our first introduction to Australia. It was love at first sight and we've been back many times. The first thing we learned was that Cairns was pronounced "cans". Cairns is close to Townsville and is the city where we always stopped to access the Great Barrier Reef and as a stopping off place before going on to Papua New Guinea for diving.
Along the way and several visits under our belt, we learned that Melbourne is not pronounced "mel-born" but rather "mel-bin", Canberra (the capital) is "can-bra" and Brisbane is "bris-bin". Sydney is still Sydney although with an Australian accent it is a little more romantic sounding (think Crocodile Dundee).
Of course even the country is not always referred to as Australia but rather Oz. Why? I'm glad you asked. Australians love to shorten words. The people are called Aussies and the shortened version of Australian is Aus which sounds like Oz. Think that's confusing? Take a look at the words below.
Brekky is breakfast
Maccas is MacDonald's (BTW Burger King is called Hungry Jack's because someone had already trademarked BK in Australia when the company wanted to open the franchise there)
Mozzie is a mosquito
Servo a gas station
Bottle-o a liquor store
Docket is a bill or receipt
Fair dinkum - true, genuine
No worries has of course been adopted by many to mean no problem
So as you see, English is not English everywhere it's spoken--at least not the "Queen's English" as so many refer to the original English as it came from the United Kingdom which was known as Great Britain or the Commonwealth or. . .It does get confusing. We always claim to speak American. People just nod and smile in understanding.