The word for difference in Russian is разница. It declines like this:

The first joke I ever heard in Russia was in 1986, and it involved the word разница. It went like this.

It's not the most sophisticated joke, but being in Russia at the end of the Soviet period, it amused me quite a bit.

During the Soviet period the government did not permit much humor or mockery on public television because they were simply afraid of it, like most dictatorial regimes that lack the wisdom and strength to endure public criticism. Generally, on the individual human-to-human level, I think that mockery is a sign of a weak self-image on the part of the mocker, and I don't have much respect for it. But when it comes to dealing with governments and public institutions, we should always allow both criticism and mockery. When a government forbids either one, it is trying to prevent its citizens from inducing change. A healthy democracy will survive both criticism and mockery as the free market of ideas slowly brings humanity to better things.