In Chapter Nine, Squealer announces that everyone—except the dogs and the pigs—will have their food ration cut. When making this announcement, Squealer chooses his words carefully: he says a "readjustment" of the ration, not a "reduction," even though that's exactly what it is.
This is an example of a euphemism: a word used instead of one that might sound offensive or upsetting. In other words, Squealer knows that if he tells the animals that their rations have been reduced, the animals will be upset and more difficult to control. In contrast, the word "readjust" implies that this decline in food is a necessary and temporary situation.
Moreover, Squealer uses this euphemism because Napoleon does not want the animals (or the outside world) to realize just how bleak the food situation really is. If people realize that the animals are almost starving, it will look as though Napoleon cannot successfully manage the farm.
"Readjustment" is a euphemism for "reduction"; it is a term which is much less harsh. If Squealer had said that there would be "reduction" of food, the animals might understand the fact that they are going to have less to eat, while the pigs and dogs are going to have more. By using ambiguous words like "readjustment", and by giving pompous explanantions for his actions which are far beyond the average animal's ability to comprehend, Squealer is able to make the animals believe that they are not being victimized so that the pigs can have more for themselves. Squealer tells the animals that "a too rigid equality in rations...would have been contrary to the principles of Animalism", and that, despite appearances, "in comparison with the days of Jones, the improvement (in their quality of life is) enormous". The animals, who are accustomed to being followers, don't remember what it was like in the days of Jones and also don't fully understand what Squealer is saying. They accept their situation, however, because Squealer is their leader and because what he says sounds wise. By virtue of his position and intelligence, Squealer manipulates words to blur the line between truth and falsehood, and in this way is able to fool the working animals and keep them in subjugation.