What is unusual about the Party's mottos?
WAR IS PEACE
FREEDOM IS SLAVERY
IGNORANCE IS STRENGTH
Each one seems to contain two contradictory words? But I'm not too sure about how they are unusual... unless that is it?
The first answer here has a good, detailed in-depth discussion of why the Party chose those mottos. However, it is not clear to me that that answer really goes with your question.
In response to your particular question, I would say that you are right -- what is unusual about the mottos is simply that they seem to (and do) contradict themselves.
You would not expect a party or, in this case, an entire society, to be built around ideas that cannot possibly be true. But that is the case in Orwell's vision of the future. The first answer gives a good discussion of why he might have had the Party use these slogans.
On one side of the debate, it could be argued that the contradiction is deliberate on the party's behalf. The party is convinced in keeping its citizens as the same and locking them into roles where they are able to blindly follow the directives of the government, without a sense of questioning. In offering quotations that seem to speak a level of truth, the expressed purpose would be that citizens are not able to identify or speak out against these ideas. Additionally, their contradictory nature is spoken with such a certainty on the part of the party that it is taken as truth. The doublespeak offered by the party in its slogans could be the desire to speak truth and ensure that everyone follows or it could be a test of loyalty to the Party. If one were to speak out against it, then one could be accused as being disloyal. It is a bit unclear whether Orwell designed the slogans to represent the potential end or undoing of the government or the substantiation of it.
. this quote or slogan is filled with drastic ironey because not only are the statements contradictign themselves, but the citizens domt seem to notice the ironey of this statement and simply memorise it as if it were their ABC’s. This quote is also the reader’s first encounter with the idea of doublethink, the partys process of weakening an inidvisual mind’s strength and independence and forciong them to live in a constant state of propaganda induced fear. Through doublethink, the government is able to force its people to willingly accept basically anythign they say, even if it makes no sence whatsoever. For instance, the Ministry of Peace is in charge of waging war, the Ministry of Love is in charge of political torture, and the Ministry of Truth is in charge of doctoring history books to reflect the Party’s ideology. This slogan is an important symbol which shows the hidden power of the government over its people by saying that even though the slogan is completely illogical, the people are psycologically so influenced by the government that they turn a blind eye toward anything else. In other words, the government is able to conince people that “war is peace” by telling the people that having a common enemy helps keep the country together in many ways. With “freedome is slavery” they explain that they will succeed only if they are united, if they try to go off on their own, then they will fail. By the same token, “Slavery Is Freedom,” because the man subjected to the collective will is free from danger and want. And “ignorance is strength” because the more people ignore the contradictions of their slogan, the more powerful the governments power gets over its people.