Nadsat

Nadsat is a slang language. It was invented by Anthony Burgess when he wrote a book called "A Clockwork Orange". The book is about a teenager called Alex. Alex speaks Nadsat in the book. Stanley Kubrick turned the book into a film, also called "A Clockwork Orange".
The name of the slang language "Nadsat" comes from Russian. So do many words in the language itself. In Russian, numbers between ten and twenty end with -"nadsat". This is like the way the same numbers end with -"teen" in English. So "Nadsat" means 'teen'.
Although there is 1950s Russian slang in Nadsat, there are other languages too. However, most words in Nadsat are English or variations of English. One type of English variation used is rhyming slang.