This is a very common problem, and a very annoying one. Most children seem to have a sixth sense for picking up words they perceive as “naughty” or “forbidden.” And then they especially like to use them in front of your friends or associates. No longer do we have to wonder where they hear them: they hear them everywhere—in every movie they might see a bit of in your living room, from teen-agers and young adults, from slightly older children. I must confess I am frequently shocked at language used by young adults from “good” families—“He’s a piece of s---” “I told him to f--- off” “I was really p---ed.” To me this is simply not acceptable, even though it appears to have become part of our ordinary word usage.
In my experience, ignoring the unacceptable language does not work. The child perceives ignoring in that situation as acceptance. I would use “time-out” whenever a term that you cannot accept appears. And before he is sent to time-out, I would get down on my knees so my eyes are level with his, lock my gaze into his and say firmly, “You may not talk that way in this house. Do you understand me?” You should not have to do that too many times before he gets the message.
Our parenting advice is given as suggestions only. We recommend you also consult your healthcare provider, and urge you to contact them immediately if your question is urgent or about a medical condition.