The use of foul languge in and of itself isn't the problem to me. The problem I have with the people use foul langauge normally falls in only one of two classes "the person who doesn't KNOW how to properly use foul langauge" and "the person who over uses it just for the sake of using it".
Both make for very boring communications. The value in a well placed F bomb for example is both in its delivery (context) and the amount of "shock" factor or emphaisis it lends to whatever point being made.
Consider this...if you have two friends...one uses foul words as everything from commas to periods when they talk..every other word is cuss word regardless what they are talking about - heck even when they are happy. Then you have another friend who rarely ever cusses and you can count how many times he/she has dropped an audible F bomb on one hand in the past year.
Now tell me -- both your friends explode over an issue....who's use of language is going to grasp your attention stronger -- the person who you are used to cuss constantly or when that other friend that never cuss blasts a big cuss word at you?
Then like I said its also the context of the words being used. The spoken word is an art form that few people understand, its like comedy you over use the same joke it gets less funny each time....well cuss words are meant to alert or exclaim....over use them to much the effect wears out.
Btw I don't agree with little kids being encouraged or taught to cuss....I'd say at least to 13 try and provide them at least some measure of innocence however small.