I know this is something that seems to come up alot and pervades today's society: foul language.  Here is what St. John Chrysostomos said about foul language: "Above all the other members, then, let us control this; let us bridle it; and let us expel from the mouth railings, and contumelies, and foul and slanderous language, and the evil habit of oaths."  Foul language can often be offensive to other people, who are the receivers of the words said by another.  When someone says foul language, dont respond back with foul language, but rather, speak with kind words.  Foul language will sometimes involve lack of charity.  I know that it is often use in casual conversation as well, but rather, try not to use them, and use other words, or dont speak at all.  Ask yourself this: would Jesus say all these cuss words that exist in our society today?  I highly doubt it.