It's easy to pick up swear words and you can't really blame children for it. Most of them think it is part of normal language. The worst is when your little enunciator is only two years old and starts swearing like a sailor in his high chair. Of course the most likely place he or she heard these words in the first place is probably from you.
Still it is very disturbing seeing this little angelic being cursing like the devil even if it is kind of funny. Some kids swear just as you feel that you might come out with a few curse words of your own.
The upside here is that if your kid is swearing it is a good sign he or she is listening to everything. It is natural for a kid to pick up words fast and a sign that he or she catches on quickly. The thing is too that they will catch up on words that have some kind of emotion attached to them.
The worst thing you can do is encourage a baby to swear by smiling or laughing. This is just positive reinforcement and he or she will just do it more. Swearing can get them into big trouble if they go back to school. Best to nip this kind of thing in the bud before they are called down to the principal's office or you get that call at home that your kid is a bad influence on the other children in the home.
One way to stop your kids from imitating you from swearing is to stop doing it yourself. Simply avoid bad language. Try alternative expressions to swear words such as hogwash, phooey, nuts, shoot or blast it. This also makes your kids laugh and it just does not sound as bad as the real cursing.
One of the challenges here is that a kid under the age of three is often saying words with little ability to know what they mean. It is after their third birthday that the comprehend the meaning of what they are saying more. Once your kid is over three years you are more likely to get a response if you say something like 'This is not a word we use in our family.' Or 'This is not a polite word.'
Another trick is to make the word and not the child bad. Do not shame the child for using the language. Instead point out the bad word and encourage the kid to move away from it psychologically. A shamed kid is also more likely to swear out of nervousness and it becomes a vicious cycle.
If your four year old swears a short time out might help. You could also try taking away a favorite toy. If your older kid swears then it is time for grounding, withdrawal of allowance or time spent in their rooms. Forget the old washing their mouths out with soap. Nobody does this anymore.