Newspeak
Newspeak is a concept from the book 1984 by George Orwell. It is based on English, which is referred to as Oldspeak in the novel. Newspeak is the language that was created by Oceania. It is a language whose vocabulary grows smaller each year. For example, the word for "bad" becomes "ungood" in Newspeak. It  becomes a word simply meaning the opposite of "good", with the prefix "un-" meaning "not". In the novel, this language was made by Party members as a means to limit human thought to the absolute lowest. This results in the people not being able to question whatever the Party tells the society.