I'm going to stick my neck out here. I'm really very concerned about many of the punishments suggested in an attempt to curb swearing.
First and foremost, our reactions and responses to our child's picking up unpleasant words gives those words value. Shock value, attention value. Until then, if I have read the post correctly, those words had no use in the home. Our children are learning in leaps and bounds at this age, and we are usually proud and excited when they come home with new acceptable words.
However, our very youngest and most trusting of children have ABSOLUTELY NO WAY OF GAUGING THE MEANING OF THESE WORDS. They understand that many of them are exciting exclamations that someone else might have yelled out. As someone who is very interested in language, and who has worked with children for a long time, I've observed that time and again, the words our children hear that are loud and exciting are certainly repeated just in pure interest.
In essence, they are trying out something new.
This is why punishing them for a crime that was not deliberate or even "disobedient" is so incredibly unfair to our children. Add to that the physical hurt our children experience due to spankings, hot sauce, or soap in the mouth-- if we want our children to grow up trusting us, we seriously need to consider if what we are doing is in the best interest of our children or our selves.
When my son swears, (he is nearly two) which is occasionally, I just ignore it. It goes away. It will sometimes return, but we just let it go. Long explanations only give the situation far more attention and reinforces the likelihood of it happening again. I could never punish my child for something that he is completely unaware of doing.
With older kids, potty talk stays in the bathroom, where they are welcome to giggle and say "poop" and "fart" to their hearts content. They are going to say it whether we are around or not; my method is to make it clear that there is a context for this talk and that it doesn't belong at the table or around other people who don't enjoy it.
Foul language, on the other hand, is sent to the speaker's room (or if they share a room, a place in private) where they can swear all they want as long as others can't hear them. The point, once again, is to let the child know that the language is unpleasant and others don't want to hear it. This is only used with children who can conceptually understand "good" and "bad" language and why, socially, people find it unpleasant.
Our children are their own people. Their bodies are their own. By forcing punishments that hurt them physically (or are unpleasant) they will be angry with us and the problem will just go underground. They may even do these things to siblings. We must be careful with what we teach our children. They own their mouths, and while we don't always like what we hear, our children were not put on this earth to please us, but to become their own authentic persons. When we guide them to learn how, and where, to best express themselves and get along with others, we do them a valuable service!