Time and place. It teaches them that in the playground with your mates (eg the pub for adults) is fine but infront of grown ups (eg a formal setting for adults) it is not.
I know everyone swears, but most people swear because they can't find any other way of expressing themselves.
Children aren't children for long enough as it is nowadays.. they don't need to know swear words, they need to remain children as long as possible. Being a child is all about innocence and naive, avoiding the harsh reality of life for as long as possible. Swearing doesn't exactly fall into that category.
Its rude, its disrespectful if you use it against someone and shows that you lack vocabulary.
Because swearing in the adult word is usually used in violence
Yes it can be somewhat 'desirable' to use in adult conversation but the origin of swear words are usually negative.
so that they show respect to their parents?
I've always thought it's weird that when you're a kid, you have to be careful not to swear around adults. When you're an adult, you have to be careful not to swear around kids. It's completely bizarre and non-sensical.
But I'm sure if I ever have kids it will be exactly the same because I've been brainwashed to conform to these ridiculous rules.