system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Where did certain 'swear' words come from? ... And what/who decided them to be rude?
gpt
Disappointingly, the most accurate answer is: "It just happens". Basically, society as a whole simply agrees that certain subjects are taboo (usually sex and unpleasant bodily functions), and that some of the words associated with them are taboo.

And different cultures have different ideas about what is and what isn't taboo. For example, the German word "Scheiße" (pronounced "shy-suh", if you're wondering) means "shit", but in some contexts it's not considered offensive at all: "Scheißwetter", for example, is best translated as "lousy weather".

It's really what the words refer to that is considered offensive; but it's common that the most offensive words tend to be shorter and of Anglo-Saxon origin, while longer, Latin-based words are less offensive or even perfectly respectable. The "C-word", for example, is one of the most offensive words in the English language, but its Latin equivalent "vagina" is usually a pretty inoffensive medical term.

I say "usually" because it depends somewhat on the context, and because also the offensive nature of the word you're avoiding becomes attached to the less offensive word, which is why at least one mother once complained that her daughter had been exposed to signs advertising a play called *The Vagina Monologues*.