how does a society charge up swear words? why is "fuck" a swear word and not "condom." wait, i think it is sometimes. but why some words over others?

my mom told me that "fore" in cantonese is (phonetically) "fugyiu." so it sounds like they're saying fuck you all day at the golf course. and "that" in chinese sounds like "nigga" in english. my friends counted once and i said "nigga" 19 times in a 7 minute phone conversation with my mom while riding bart. first of all, yes, i was that asshole talking in chinese on a cellphone on bart. and yes, i was scared of all the black people in the car for the rest of the ride. but that's not the point. why do i sound like a sista when i talk to my mom, and how did they charge up that word when heard by english speakers?

it's gotta be energy. the more energy, emotions, events, memories, etc. are stored in a symbol, be it an object or a word, the more it has weight beyond intellectual communication.