This post is 100% a spoiler for the Poul Anderson story "A Tragedy of Errors", so be warned.
The story is set on and around an isolated planet long after the fall of the Terran Empire. Communications have broken down, and so has security. On this planet, the words friend and business have dropped out of the local version of the Imperial language in favor of camarado and 'change (short for exchange), respectively. But they have been recently reintroduced, thanks to an incursion of pirates, in the novel senses of pirate and piracy respectively (as in a very sarcastic "We're your friends, and we're here to do business with you.")
The next set of travelers who arrive saying "We're friends" get shot at. Because slave has also shifted its meaning locally, to something like worker or employee, they shoot back, with disastrous results all around. The semantic shifts are eventually unraveled, but only after some unnecessary killings.
Usually, semantic problems aren't this bad. But the story (which is unfolded from the viewpoint of the second, peaceful set of travelers) vividly demonstrates what's possible when communication breaks down.