@dagmaraka,
Dumb question here....
I remember several of my language and history profs in school talking about Czechoslovakia, which is what the place was called then, and they all said the same kinds of things, i.e. that the two groups of people comprising the place were basically incompatible and that the place would ultimately split up (kind of like what they're saying about the U.S. now...) They all said that the Czechs were basically intelligent, enlightened, hard-working, industrious and all that sort of thing, and that the Slovaks were legitimate candidates for sorriest bunch of losers ever assembled under one flag in Christendom, i.e. no redeeming features at all.
And yet from what I read the two languages are very closely related and you wouldn't figure there to be any genetic differences bigger than little.
That's the question. How do you get that much differentiation where there don't seem to be any real differences??