But joking aside, it was the Brits who originally called it soccer. When the game was first brought to the US (and Australia) by the Brits it was a very different game than it is today. Rugby and gridiron football were once in line with British football (which had basically no rules that most would consider a blood sport), as the game evolved in each region (to include the UK) they grew apart but were still called Football. We call it soccer to differentiate between the two games.
Same with our accents: The British accent during colonial times resembled more that of American English than the "English" English of today. This is why the Australians have an accent that is closer to the "English" brits speak today (their relationship in history is closer to present day than that of the US).



Informative x 1