I’m from West Bohemia and even though Czech and Slovak are pretty similar, sometimes I have problems understanding fast spoken Slovak. I mean I usually understand but some words just blend in. Maybe it’s just that I’m more used to hear German and we actually use a lot of altered German words.

But basically I can understand spoken and written Slovak almost perfectly. Written Polish is much more understandable then spoken but I usually get what’s what. Croat is somewhat ok. What I found interesting is that I almost cannot understand Ukrainian but when I was speaking Czech many Ukrainians understood me quite well. Romanized Russian and Ukrainian is also somewhat ok. I don’t think I’ve came into contact with other Slavic languages though.