Many times when your preschoolers is using words that are inappropriate, the inappropriateness is actually with the adult. The child has no idea what is appropriate and inappropriate in the social concept. However, what they do know is that they were getting response from the words they are using. So the more you desensitize certain words that they find silly that we know is inappropriate but they find funny, the hard it is for them to get arouse out of you the less they gonna want to use that word. What we do in our classroom in those situations for example, there's a word that some of the children have used that are creating silliness and laughter is we actually say that word, and we show them what the word means. We even asked them, what does this word mean, what does "poop" mean for example. They will talk about it, and once they realized that it's an actual word with gray little, rising coming out of the adult they tend to use it less and realize there's no point in doing it.