I'm ashamed to admit I learned the most about the dialect in A Clockwork Orange from it's Wikipedia article. I guess this is just one of those times where wiki trumps a lot of the other sources. However, what I found was nonetheless interesting. The following is a quote from Wikipedia which explains Nadsat and why it was used in the book and in the film.
"Burgess, a polyglot who loved language in all its forms, was aware that linguistic slang was of a constantly changing nature. Burgess knew that if he used modes of speech that were contemporarily
in use, the novel would very quickly become dated. His use of Nadsat was
essentially pragmatic; he needed his narrator to have a unique voice
that would remain ageless while reinforcing Alex's indifference to his
society's norms, and to suggest that youth subculture existed
independently of the rest of society. In
A Clockwork Orange, Alex's interrogators describe the source of his argot as "subliminal penetration."
http://en.wikipedia.org/wiki/Nadsat
I think the idea of creating a slang for the future is quirky and definitely shows artistic intent. A couple of my favorite words from the Nadsat dictionary are...
Pretty Polly Money
Nochy Night
Millicent Policeman
Lewdies People
Ded Old Man
Bugatty Rich
Yarbles Balls, testicles
Pooshka Gun
http://soomka.com/nadsat.html
