Cadaver747: Some words are recognizable but way way different, for example I would never get a proper understanding of the Czech word "dopis" which means "a letter" (writing), yet I would instantly realize that it has something to do with writing with the emphasize on completing the action of that writing or even adding something extra after. Literally it would mean to finish the writing, then to add some more letters to it, that is "dopis" for me.
Some words are completely alien, for instance "sklo" is okay and I would understand that it's something made of glass, most probably it would be the glass itself (glass for water, not material) but "pohár"? No, I don't know such words.
At least curse words are highly recognizable.
Curious, I think linguists are full of joy all the time.
Yeah, nouns are the most problematic words. Many of them are similar, but many of them are also very specific in the various languages. Many such cases even between Czech and Slovak.
When I'm trying to understand Polish for example, I most often get stuck on some key noun due to which I don't get the exact meaning of the sentence. But I find most of the verbs are usually somewhat similar.
As for "dopis", it can also mean that in czech. A noun of the activity you describe. "Dopiš to!" is telling someone to finish writing something. But we also use it for letter itself.