Peer pressure I can go along with.............but somewhere along the line they had to have learned these words from somewhere.........and that somewhere is usually an adult.
The utterance of those type words, including the word "damn" elicit a financial penalty in this house.........my 6 year old tends to heavily supplement her allowance when daddy is doing yard or auto work!!!!!
Kids don't learn curses from adults. Kids learn them from other, older kids. Kids learn one set of words to use at home, and one set to use around their friends.
Now, parents could do more to choose their kids friends but that doesn't work too well if they go to school or spend hours hanging around the mall.
You'll probably laugh, but I didn't know what the "f" word actually was until I was 14 and read it in a book, because I hung out mostly with other homeschooled kids, there was always a mom around, and that kind of language brought swift punishment. Teachers aren't allowed to lather young tongues, so they can't control the language kids use in the halls.