As I see it, a lot of things are categorized as sins because of the effects it has on the one committing the sin and on others as a result of that action.
For me, cussing or cursing is often problematic both because of the meaning of the words being used and their emotional and psychological (and spiritual) effects. Many curse words refer to an act as disgusting or demeaning, such as the sexual act or normal biological acts or parts of the body. Would Christ have us view these things as demeaning?
Why are some parts of the body declared disgusting or bad? They are just as good as any other part of the body. Then why should we profess them not to be? It is only their improper use which can be disordered and sinful. But “cuss” words seem to imply that they are somehow bad, or maybe its just that they emphasize their disordered or sinful uses.
For example, “Love you!” or even “Make love to you!” or even “I’ll have sex with you!” could never qualify as curses, only as statements of affection or attraction (the latter does not necessarily imply love, but neither does it deny the possibility). They simply do not not convey disgust or hatred.
And yet “F*** you!” certainly does qualify as a curse, even though it technically can mean the same thing. The truth is that the dominant quality in the term “F*** you!” is one of hatred or at least spitefulness. This is why its problematic.
Now, cuss words are used as normal adjectives or other parts of speech without their original intent by many these days. I don’t think this has the same degree of intensity, but it is a distortion of those terms and still carries its original meaning for the speaker, even if it is not intended, and makes true cussing all the more easier.
And its not just cuss words either- just inappropriate, even disgusting statements. How many times have I not heard otherwise well-spoken adults talk about someone being “anal” or “anal-retentive”? By the time they’ve said it many times, they may not even realize the meaning of their words. But its still there, even to the speaker. It’s not an unknown foreign language. How often don’t these terms and words pollute our speech and create a negative verbal environment without us even realizing it. Could you imagine a truly holy person saying that being a certain way is “anal-retentive” in everyday speech?
Just analyze the emotions such terms and words bring up in ourselves, or how others would perceive them from the outside.
On the other hand, I think “bad language” has its place. Something that is truly disgusting can be referred to by a cuss word, in my opinion. And sometimes this is the best way to truly distinguish something pure from something truly bad or evil. But such use would confine cussing to very limited use, not everywhere everyday, as is the case so often these days.
Also, if we are using “cuss” words from another language not as cuss words, but simply as exclamations and are not aware that they are “cuss words” there is no such meaning present to us and thus no sin. Such was the case of a friend of mine who used the word “shmuck” in this way without understanding of its original meaning.
To me, words like “damn” are strong words, but not quite “cuss” words.
This is all from my humble perspective. Hope it is useful!