Think back to your younger years. Where did you learn the meaning of “street” words, i.e., cussing, swearing, body parts? Probably from your (slightly older) friends, who learned from their slightly older friends. Perhaps your parents and their friends had a salty vocabulary. Young people don’t want to look weak, dumb, or naïve, and a trash mouth is a quick and cheap way to sound sophisticated and street-smart.
Grown-ups do it too, of course. Occasionally they will be aware of their bad manners. “Pardon my French,” they’ll say, thus insulting the French people too. One of the ways in which you can live your faith is to control your trash mouth: “Do not let any unwholesome talk come out of your mouths, but only what is helpful for building others up according to their needs, that it may benefit those who listen” (Ephesians 4:29).
Why does this matter? Swearing (i.e., using God’s name to guarantee the truth of your words or to add emphasis) is unnecessary if you have a reputation for telling the truth. Cursing (i.e., calling on God to punish somebody or something for you) isn’t your business. God will handle any damning that needs to be done. Body vulgarity is often used to ridicule somebody else. Sexual vulgarity is not mere talk—it may send everybody the message that you approve of committing adultery.
Here’s God’s filter for your mouth: Is what I’m saying helpful for building others up?