my parents used a lot of foul language as well (and i am prone to in times of frustration). I taught my children that they are allowed to say whatever they want, no matter what. my SO flipped out. when they were younger, we talked about being mean to people and how it makes them feel. we also talked about being able to express yourself in an educated manner and how people perceive you based on what you say. so far (knock on wood), they are compassionate and speak well for themselves. they are able to articulate why they are frustrated or how something is impacting them rather than just saying a random string of profanity or calling someone a name because they're upset with the situation.