there's been an alien invasion. they put microchips in our brains, now anyone that says a bad word, their brains will explode. the only people to survive this are babies because even children of four years old will fail. these are words we use to express ourselves, they come out of our mouths on impulse therefore making it impossible to do. even if we manage to compose ourselves, we would still die. as humans we have a complicated way with our languages. some words sound similar to curse words because of our complex English the alien's won't be able to tell the difference in other words putting our lives at risk. something tells me that the alien's are not ready to learn our language . like how horrible and horrific mean the same thing but terrible and terrific are opposite's. it's gonna be a lot of skill to not be able to express your anger or frustration with words and a whole lot of luck for the alien's to understand what you are saying.
I decided to add alien's in the plot there would be a reason for curse words to disappear, I mean come on, 😐you think humans are actually going to do that.