As an Australian i can pretty much say we are pretty open when it comes to swearing. S#@t, F&(k can be commonplace words in a sentence. As for my son (2yrs old) i guess he picks up the language (my wife and i do swear, me more than occasionally i guess... the words are just so flexable they fit any situation! :) ) but i believe it is up to my wife and i to correct him. It would be naive for me to think he doesnt know the words exist or to a small extent what they mean, so i teach him that they are inapproprite for him to say. Yes we did have a week where he thought it funny to say the f word, and yes it was slightly embarresing, but he now hasen't said it in 3 months. Its funny to see how different each country reacts to swearing, here even our ad campaigns have them "So where the bloody hell are ya!"