Sad to admit that I am a rather fluent and natural swearer..
I can avoid it pretty easily at work when people I don't work with are around and I have learned to be cautious around people I don't know for sure are "safe". But once I have clearance..booyeah! My language takes on or kinds of color, sad because if it is possible to be good at it, I am.
So as a Player I sometimes let the occasional curse slip out at the table, I try to keep it pretty tame most of the time though because we are in a sort of "family environemt" when we play (there are no chidlren around, we run the ages of 25-@42) so when I do swear (mostly because my luck with the dice is pretty bad and I always manage to roll 2 1's in a row at the worst possbile time..hahah!!) I do it 'under my breath' more or less.
Now as a DM it's an entirely different story.
I am much more relaxed and if the dice go bad I dn't care because I have all the npcs and monsters I need so if they flub, no big. (I may be disappointed how things go but as long as everybody has fun it's all good.)
However- when it suites my npcs they have a viriaty of "naughty language"
Now I do play with 2 ladies so I always avoid using certain phrases and subjects I have makred mentally as out of bounds.
Likewise there are
certain things, in game,
I would Never do or allow to happen.
(But that is a rather mature topic and would hijack the thread.)
So the game I run can be rather Mature but never "Adult"
I
I try to come up with creative sayings the are, IMO approprate for particular npcs. Pretty much any and every "evil humanoid" will curse and swear foul oathes, pretty much in their native language. If a pc speaks that language I will tranlate it if they wish. A lot of the time I will describe the curse rather than actually state it. "The orc sets off an a tirade describing rather unsavory acts involving your father and a farm animal.." kind of stuff...
A recent encounter with a drow that fumbled one of his weapons while blind fighting in a circle of '
darkness' had a brief , "You hear a clash of metal and a clatter followed by an obviously foul curse in any language judging by the tone used ,as a sword slides out of the darkenss and across the floor."
Sometimes it is done in the Common tongue and can be rather amusing, as in the Sunless Citadel, "Yusdrael" (sp?) went off on a royal tirade in the common tongue and got so worked up that I finally not only did I have all the players at the table laughing but got myself busted up too. (they gave me some "bonus dm xps" for it, haha!)
SO depending on the group you are with there may be times it is appropriate and can add some color to the game. But for the most heroes of course should not curse.
Anti-heroes, yes and villains absolutely! (Although I would probably not have a LE BBEG that has a high INT score not curse unless the pcs really puched him over the edge.) I use it to set the tone and add a dimension to the game.
