I'm re-watching Costa Gavras' classic film Z, a semi-factual account of the rise of the Junta in the 1960s.
The film ends with a long list of things banned by the junta, which include "strikes, labor unions, long hair on men, mini-skirts, the peace symbol, the Beatles, Sophocles, Tolstoy, Aeschylus, Socrates, Eugene Ionesco, Sartre, Chekhov, Mark Twain, Samuel Beckett, free press, new math and the letter Z, which in Greek means Il est vivant."
So I guess the first question is, does Z really mean or stand for "he still lives" in Greek?
Was the letter really banned, or is that just hyperbolic? How did typewriters work?
Of course not, that would be absurd since the z sound is used extensively in Greek and there's no other letter in the greek alphabet replicating the same sound, like K and Q in English for example.
The greek name of the letter Z (ζήτα, pronounced zíta) doesn't mean "he still lives" in Greek, however the name used in American English (zee) does. The title was intended as a reference to the chant used by protesters after Grigoris Lambrakis's murder, "ζει, ζει, ζει"(he lives, he lives, he lives). As to what Gavras means when he says the junta banned the letter Z, I can't really tell. I'll admit I haven't watched the film, so perhaps I'm missing something important .
I would probably write a more in depth reply regarding Lambrakis, whose murder served as an inspiration for the film, but I'm on mobile, so I hope this at least answers your question. I suggest you look into it yourself if you're interested in the actual historical events "Z" was based on.