The syntax and theory of newspeak makes a quite
fascinating appendix at the back of the book. It is reproduced, along with a full dictionary, in the webpage
choasmind mentions above. Not many authors have the balls to create a whole new language to play with in a novel.
Anthony Burgess'
nadsat, from a
Clockwork Orange is another example though.
Not only is newspeak a method of controlling speech, but also thought. It actively encourages only orthodoxy, with all unorthodox words, by reducing the size of the vocabulary. The premise is that if an idea cannot be expressed as a word, then it cannot be thought - and thoughtcrime, and the eradication of it, plays a major part in the society of 1984. The example Orwell gives in the appendix is the meaning of the word free. In newspeak, 'free' can be used only in the context of 'free from lice', the meaning of free as in free speech or free thought simply no longer exist. They are not valid newspeak, and to use the word in that way is a crime, even to think it is thoughtcrime.
The (ambitious) aim was to do away with what we know as the the English language (Oldspeak) altogether by 2050, replacing it with wordless noise, like a duck's quaking, called duckspeak. Duckspeak takes newspeak to new extremes; absolutely no thought is required to use it - only orthodox sentiments can be expressed. Winston, the main character from 1984, hears a party member using duckspeak during the course of the book, and it is disturbing.