Orwell was a big believer in the power of language to free or to oppress. In 1984, the Party uses “Newspeak” to control people’s thoughts by way of language. Consider the following passage from 1984, when Party member Syme talks about the future of Newspeak:
The whole literature of the past will have been destroyed. Chaucer, Shakespeare, Milton, Byron – they’ll exist only in Newspeak versions, not merely changed into something different, but actually changed into something contradictory of what they used to be. Even the literature of the Party will change. Even the slogans will change. How could you have a slogan like “freedom is slavery” when the concept of freedom has been abolished? The whole climate will be different. In fact there will be no thought as we understand it now. Orthodoxy means not thinking – not needing to think. Orthodoxy is unconsciousness. (54)
And these passages from the “Appendix”:
The word free still existed in Newspeak, but it could only be used in such statements as “This dog is free from lice” or “This field is free from weeds.” It could not be used in its old sense of “politically free” or “intellectually free,” since political and intellectual freedom no longer existed even as concepts, and were therefore of necessity nameless. (310)
Newspeak was designed not to extend but to diminish the range of thought, and this purpose was indirectly assisted by cutting the choice of words down to a minimum. (310)
Newspeak, indeed, differed from almost all other languages in that its vocabulary grew smaller instead of larger every year. Each reduction was a gain, since the smaller the area of choice, the smaller the temptation to make thought. Ultimately it was hoped to make articulate speech issue from the larynx without involving the higher brain centers at all. (319)
And, finally, the following Calvin and Hobbes comic strips:


As far as Orwell is concerned, language is the foundation of thought. This same sentiment is echoed by the Spanish essayist Miguel de Unamuno, in his essay “From Sound to Vision”:
And history, vision, the contemplation of the destiny of a people, of what a people makes of itself – people number one – that vision, where does it come from? It comes also from the word, from speaking, from language. Logic comes from logos; that is to say, “verb” or “word.” And it also means “reason.” And “reason” comes from rationem, derived from a verb, reri, which means “to speak.” Even today, in Catalan, enraonar and raonar mean “to speak.” And to speak is to reason is to think. Logic is not, in the end, more than grammar. And philosophy is philology. And thinking is feeling: one thinks the feeling as one feels the thought. (Miguel de Unamuno, Obras completas, vol. 4, ed. García Blanca [Madrid: Esclericer, 1968], 497.)
Your thoughts can only be manifested through language, through words. If you have a thought that cannot be expressed through your language, than you cannot think that thought; it doesn’t make sense to you. Language defines the limits of what you can think. It reminds me of my old high school writing portfolios, whose covers said, “How do I know what I think until I see what I say?” In the world of 1984, no one can see what he says, and therefore, no one knows what he thinks.
In 1945, Orwell wrote an essay called “Politics and the English Language,” in which he lambastes politicians and academics for not being precise with their language:
A man may take to drink because he feels himself to be a failure, and then fail all the more completely because he drinks. It is rather the same thing that is happening to the English language. It becomes ugly and inaccurate because our thoughts are foolish, but the slovenliness of our language makes it easier for us to have foolish thoughts.
In 1984, the absence of a particular word also means that the concept no longer exists. As Syme says, if there is no word for “freedom,” then there can be no concept of “freedom.” The word ungood, while expressing “not good,” does not in itself suggest “bad.” In Newspeak, there is no positive concept of “bad.” It is only defined negatively in terms of good – ungood. Syme says that, once Newspeak is definitively the language, there will be no such thing as thoughtcrime, since the constraints of the language will make it impossible for you to think anything that the Party doesn’t want you to think.