I'm a purist.
Now, I have to clarify that statement.
I like the english language... it is the most expressive language there is, because it "borrows" from many other languages. French words exist in our dictionary, as do Spanish words. We borrow, plagiarise, steal, accommodate.
But language is ever evolving. New words appear with new situations, new technologies, new trains of thought.
New swear words are constantly appearing, too. I don't understand a lot of the new swear words. Give me the old fashioned "F---", or "C---". I think everyone knows these words, and I defy anyone to tell me they haven't said one of them in their lifetimes.
Expletives, they are called in literary terms.
I don't swear much, but this is something I wrote recently: "A well placed expletive can punctuate a point quite nicely". I believe this whole heartedly.
Anyway, I'm a purist. The use of expletives within my writing manifests itself sparingly. Some would say that the use of such is unnecessary, but bollocks to them! Even Shakespeare used a good bit of "vile language" at times.
Anyway, this is my question to you.... Given that you started reading a book, became engrossed, and enjoyed the first chapter... In the second chapter, swear words appeared. How would you feel about that?
Oh, botheration! The stinking clock tells me my blathering time is up for writing gosh-darned posts in this forum. Hell and darn!
I think expletives have a place in all narrative media. Sure these are "trash words" that should not be used in polite conversation, but polite society and conversation are rarely the subject of interesting stories. Imagine having a crude character (who is learning to be better, if you like a positive moral), but you can't describe any of the crude things they do or any of the 'colorful' language they use beyond to just flatly state that the character had a sultry past. If you really want to develop that character you need to do more than just use demure words to describe some action, you need to describe what the character is doing or saying that is specifically vulgar. I agree that you cannot just appeal to authority to back up your reason for using them, but if they truly add depth and meaning to a character, they serve a purpose and should be used.
Foul language also known as cussing, swearing, dirty mouth, foul mouth and garbage tongue is so prevalent now that hearing it doesn't move me like it used to. If I see it in writing its a bit different because I know the author knows that anyone who sees it will know what was being conveyed at the time. That's the difference between hearing it and reading it - the permanence. As part of a story I understand its use but using it excessively when the event doesn't warrant isn't in good taste because it becomes as slack as saying "Cool" for everything.
I think using expletives is sometimes warranted in books. Some characters would swear. It is a part of who they are. I feel they are fine when used appropriately and for a valid reason. It would bother me if they are just excessively as a crutch for the writer's lack of writing skill. Expletives do add impact to phrases when used somewhat sparingly.
To me I feel the same way when I hear someone speaking. Someone using curse words occasionally doesn't bother me. However, an individual who can't complete a single sentence without assorted expletives makes me question their vocabulary.
I, myself, do not curse in my everyday speech. I do not write expletives in any of my stories as well, since I want it to be available to the widest audience possible (Young and old). That being said, there have been times that I've heavily debated putting a curse word in the dialogue for dramatic effect. Theres something that seems so dramatic about it, especially if the character's persona is one that would meld with it well. I don't use them though, and opt to use other methods for effect. Take the Percy Jackson series for example. Riordan often says that his characters "Let out a curse in Greek" although the characters themselves are being vulgar, the reader is not exposed to it.
Personally, I have no issue reading vulgar language. I made it through all the A Song of Ice and Fire books without a problem. That being said, it's frustrating when I have to hold off from recommending the stories to my friends because of the excessive vulgarities.
Summary: It's complicated.