Myth: The story goes that when the first European explorers saw these strange hopping animals, the like of which they had never seen before, they ask the native Australian people, the Aboriginal inhabitance, what these creature were called. They replied "Can-ga-roo" which in their language meant something along the lines of "I don't understand your question". The explorers thought this was an answer to their question, mistaking it for "kangaroo" and the name of the animal. So, henceforth the creature was called "kangaroo".
Fact: However, according to the Oceaniaweb factfile, the above story is actually a myth. The word "kangaroo" is believed to have come from the Aboriginal word gangurru, a Guugu Yimidhirr word referring to the Grey Kangaroo. Captain James Cook's botanist, Sir Joseph Banks, first recorded the word as "kangaru" when the Endeavour was damaged on the Great Barrier Reef near modern-day Cooktown, and required the crew to stay on the mainland for almost 7 weeks repairing their ship. This gave Banks ample time to make copious notes on the fauna and flora.
Australians often refer to kangaroos as simply 'roos.
Grasshopper is not actually slang for anything in Australia. Grasshoppers are grasshoppers. Sometimes kangaroos are referred to as giant grasshoppers, but only in rural and outback areas.
There aren't slang terms for people's names.
Saying names in the back slang requires no strict rules.
Some common slang names for acid are LSD, Lucy, tabs, and doses.
Speed IS a slang name. It means amphetamines. Click the related question to find more slang.
Poppers
Tater Juice. =)
"magic"
There is alot of slang/street names for Hallucinogens like power powder, magic dust, and many more
Australians commonly refer to kangaroos as simply roos.Sometimes they may be called boomers, which is the term for a male kangaroo.
According to Rolf Harris who originally recorded the Australian Christmas song "Six White Boomers", the kangaroos' names are Jackaroo, Bluey, Curly, Two-Up, Desert Head and Snow.