vierailija
This is really interesting! Must write down that thing about zahod just in caseYes, Serbo-Croatian was the official language spoken in ex-YU (except in Slovenia and Macedonia).
Within that, there were dialects, but now for political reasons they are considered separate languages. In reality, differences are small, but apparently, B can switch from one to another pretty well and is often complimented for that. I saw some positive comments on Twitter after this last interview as well.
Kris speaks Serbo-Croatian pretty well too, but of course nowhere near B's level.
But to answer your question, Slovenians can understand Serbian/Croatian, but Serbs/Croats claim they don't understand us.
And nobody understands Macedonian, they are like from another planet.
I'm personally probably at the same level as Jan. I understand pretty much everything, I can get by with some speaking in a restaurant or a shop etc, but when you want to explain more complex things, it gets hard.
Even if you don't understand all the words, you can guess from the context. But then there are some words which mean one thing in Slovenian and something else in Serbian/Croatian. "Ljubim / Ljubim te" was discussed a few times here or the other site. It means "I love you" in Slo, but "I kiss you" in Ser/Cro. Then there are some words which can lead to funny situations. For example "stol" means chair in Slo but "desk" in Serb/Cro. "Zahod" means sunset in Slo, but toilet in Serb/Cro.
So be careful if a handsome Balkan guy invites you to watch zahod one day!
I'm not one of the linguists of the cattle but can't help comparing this with the Nordic languages.
Finnish would be like Macedonian, from a completely different planet. Norwegians, Danes and Swedes understand each others' languages pretty well (especially DEN/NOR, I would even go as far as compare them to Serbian/Croatian). Maybe Swedish would be like Slovenian although maybe not as far out for Scandinavians as Slovenian to other Balkan people.
And then of course Swedish speaking Finns (Swedish as mother tongue) have no difficulties in mingling with Scandinavians as their nunciation of Swedish is apparently easier for many to understand than "proper" Swedish spoken in Sweden.
Oh there are a few other languages, too, such as Icelandic, the oldest Scandinavian language. You can understand some words of it if you know another Scandi language but it's a different language.