Some say that the Greeks coined the term 'barbarian' because foreigners who didn't speak Greek sounded like they were saying 'bar bar bar.'
Theory: what if the first 'barbarians' that the Greeks happened upon were simply the Beach Boys in a brief yet dramatic time slip, performing their hit tune "Barbara Ann." Sample lyrics: "Bar bar bar, bar, Barbara Ann. Bar bar bar, bar Barbara Ann..."
It wouldn't be TERRIBLY improbable. After all, they get around.