My parents swear all the time - well, especially my mom. Actually, everyone on my mother's side has a mouth like a pirate. My grandma even swears in front of me.
They never did until I was 17. That was the first time I heard my dad curse (in english). He doesn't do it often.
My mom curses sometimes in front of me.
Yes. My parents learned so much filth from my sister and I. My mom uses the hard 'C' word when she really wants to scalp my sister for something.