Cursing
Jas 3:8 But the tongue can no man tame; it is an unruly evil, full of deadly poison.
I think folks who want to stop cursing but fail put all their effort into trying to tame what can’t be tamed. No matter how self-disciplined or how much self-control one has sooner or later something nasty is going to spill out of their mouth. Cursing is more of a heart issue than a problem with the tongue.
Mt 12:34 O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh.
In other words when your heart begins to overflow with anger and all kind of other nastiness, sooner or later it’s going to come out of your mouth.
There is a solution:
Ps 51:10 Create in me a clean heart, O God; and renew a right spirit within me.
Read it, pray it, until you see some results. It’s been working for me since 2005. You don’t have to use foul language under any circumstances. In the meantime, it may be best to keep your mouth closed in some situations.
Lu 6:45 A good man out of the good treasure of his heart bringeth forth that which is good, and an evil man out of the evil treasure of his heart bringeth forth that which is evil: for of the abundance of the heart, his mouth speaketh.