There are a number of strategies for stopping children from swearing. As with other behavioral issues, helping your child clean up his language requires the patience to repeat positive techniques of guidance.
Evaluate Your Own Role
In many cases, children pick up on the behavior of their parents. If your child hears you using swear words, he will think they are acceptable. Evaluate your own language and modify it as necessary to set a good example.
Be Clear about What Is Inappropriate
Many young children do not realize that certain words are considered "bad." When your child says a word that may be offensive to other people, let him know that is the case and explain why he must not use it again.
Do not strictly censor your child. For every bad word that he should not speak, provide him with several options of words that express similar ideas or feelings but that are inoffensive. Make clear to your child that you aren't trying to stop him from expressing himself.
If your child takes your suggestions and rules to heart, avoiding swearing, give him some form of encouragement. This can be verbal encouragement, or if your child is mature enough not to act entitled to a material reward, you can give him a treat of some sort.