Polish is a clusterfuck even for Croatians, Czech might or might not be, depending on the style, Polish always. There's a lot of letters in the words that we've simply discarded or simplified over here. The issue with reading a word is that you read first and last letter and roughly guess the amount of letters, and your brain starts pulling out words that fit the context, in automatic mode. So when a four letter word maps to a seven letter word with different ending, you're fucked, even if the word is actually the same in both Polish and Croatian.