A Clockwork Orange is a dystopian work set in the near-future, and so it involves a specific sort of future slang created by Anthony Burgess. He based his slang terms on rhyming slang, which is common England, where Burgess lived; a linguist, Burgess also introduced Russian terms. He called his created slang Nadsat, and intended it to create a modern-sounding dialect that would remain fresh. Since language changes over time, using contemporary terms would have caused the book to feel dated after several years. Nadsat always looks unusual, and therefore both reinforced the concept of a living future, and prevents the book from sounding like a product of 1960s England. The language is commented on by the better-educated doctors while Alex is being studied:

"These grahzny sodding veshches that come out of my gulliver and my plott," I said, "that's what it is.""Quaint," said Dr Brodsky, like smiling, "the dialect of the tribe. Do you know anything of its provenance, Branom?""Odd bits of old rhyming slang," said Dr Branom, who did not look quite so much like a friend any more. "A bit of gipsy talk, too. But most of the roots are Slav. Propaganda. Subliminal penetration."
(Burgess, A Clockwork Orange, Google Books)

Alex's sentence in the above quote would translate to mean: "These [dirty] [expletive] [things] that come out of my [head] and my [body]." Dr. Branom comments on the propaganda roots of the Russian, indicating the intrusion of Communism into popular culture. Since Nadsat is not a slang form used in the real world, it can be seen as an entirely unique language form. The book's writing thus feels more fresh and original, instead of sounding like it is set in the era of its writing.