The appendix to 1984 is Orwell's explanation of Oceania's official language, Newspeak, of which there are many examples throughout the text, such as doublethink and duckspeak, and discusses the purpose for its conception.
Newspeak consists of the A vocabulary, the B vocabulary, and the C vocabulary. The A vocabulary consists of words needed for everyday life and words that already exist but have been stripped of all shades of meaning.
The B vocabulary consists of words that have been deliberately constructed for political purposes and are a kind of verbal shorthand; all are compound words, such as goodthink.
The C vocabulary consists entirely of scientific and technical words and follows the same grammatical rules as the A and B vocabularies.
Newspeak was designed to diminish thought rather than help expression, as is the goal of other languages. Again unlike other languages, Newspeak regularly loses words instead of gains them.
Newspeak is a brilliant device on Orwell's part and serves his political agenda well: If a government can control language, it can also control thought. If there is no word for the concept of freedom, how can a person think about freedom? By limiting language, the people who speak that language are limited to what concepts exist in words.
Orwell was convinced that language deteriorated under totalitarian rule and that literature was impossible under totalitarian circumstances. As a writer, Orwell was concerned with the state of language in the world and wrote essays on the effect of governments on writers and writing. Newspeak stems naturally out of Orwell's ideas about language and governmental control.
Orwell predicted that Newspeak would be perfected in the year 2050, perhaps because he wanted to keep the fear of totalitarianism alive in his readers past the year 1984. Orwell was a visionary, predicting many things that eventually came to pass. Thankfully Newspeak is not one of them.