Is the use of swear words in a narrative piece considered a language technique? If so what would the technique be?
This is from Matthew: 5:34 - 5:37. KJV:
"But I say unto you, Swear not at all; neither by heaven; for it is God's throne: Nor by the earth; for it is his footstool: neither by Jerusalem; for it is the city of the great King. Neither shalt thou swear by thy head, because thou canst not make one hair white or black. But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil."
I had religious friends in high school who convinced me for a time to not use swear words in my speech, and part of the argument was that if I couldn't get my point across without relying on them, then I had a weak argument. It's called 'swearing' for the reason that you are drawing the force of what you are calling out to your disposal in the discussion, I believe. That's a technique, sure. It's also a stylistic choice. Derogatory implies having a negative implication. Some people might see so called 'foul language' as merely colorful, or even friendly. It depends on knowing your audience, and how they will take it.
Make note that the Bible verse above is directly prior to the 'eye for an eye' passage, so make of that what you will.
3. Filthy literature.
1887 G. Saintsbury Hist. Elizabethan Lit. x. 370 A large quantity of mere scatology and doggerel.
1959 N. O. Brown Life against Death xiii. 179 The most scandalous pieces of Swiftian scatology are..The Lady's Dressing Room, Strephon and Chloe, Cassinus and Peter.