When debating as to whether swearing is OK or not, most Christians - sometimes even those on the swearing-is-OK side - focus on the WORDS: shit, bastard, and the like. But the debate is not about the words; it simply cannot be. There is no logical reasoning to say that the Bible expressly condemned some words as wrong. Why would it arbitrarily decide to make some words from the English language wrong? The emotion could be expressed in a different way - if it was that important, people COULD get 'cheeseburger' to replace 'fuck' - so the word would become irrelevant and there would be no reason for it to be condemned. But even that is beside the point. The English language did not exist in Bible times and didn't exist until about 1400 years after the last piece of Scripture was written, so how could English words be condemned? They're merely elements of language, letters on a page, completely insignificant. 'Fuck', by itself, is nothing, just a few strokes of a pen or a few pixels on a screen; not a problem at all. Those same letters could form other words, such as 'fire truck'. There is no reason for words to be condemned.
Now we move on to the emotion behind the word. When used in the correct context, to express strong emotion and to create an impact - ie "The hurt from what they said was fucking massive" (sorry, can't think of a decent example) - there is nothing sinful about any swear words. It's just expressing very strong emotion, and conveying an impact to the listener/reader. When overused or used in an abusive sense, that is when you start to cross the line, but, when used CORRECTLY, the emotion behind the word is not sinful, either.
Thus, I feel this is sufficient proof swearing is not sinful. Words cannot be sinful by themselves, for, in isolation, they are merely words, a nothing (in contrast, no matter how you view it, murder, even in isolation, is sinful). The emotions behind swearing when it is used CORRECTLY are not sinful, either. Thus, if the word and the emotion are not sinful, how can swearing be sinful? It isn't. The Bible never speaks about English swear words, for it was written a long time before the English language came into existence, and nor does it speak of Hebrew, Greek, or Aramaic swear words (the three languages it is written in). A word simply cannot be sinful. 'Fuck' is no more sinful than 'dog'. It is when the emotion behind it is sinful that it becomes a sin, but it would've been sinful even if replaced with 'dictionary'.
Swearing is not sinful. I invite challenges to the ideas I have put forth.