Long ago, when I was eradicating casual swearing from my speech, I began by swapping the swear words for innocent words like "yowza", "geepers" and non sequitur foreign phrases like "un deux trois!" or "Cinco de Mayo!" (try it, said forcefully they work). This has evolved to non-existent words... "Jinkers" being my casual favorite as it has no sound-alike swear words the way "fudge" does. However, when something unexpected and shocking happens, such as mashing a thumb with a hammer or such, a string of implosive nonsense erupts from my mouth that would make Yosemite Sam proud. Normally this happens in private or only around folks who know me. But once it happened when I was buying some car tires & thwacked one of my fingers. Out it came. When I realized what I was doing and stopped, I looked over at the sales person. They had this shocked and confused expression. They had no idea what I had said, but I had clearly conveyed something. Perhaps this is how language began?