[sologoub]

It seems to succeed at being understandable, but I’m guessing it will be on par in difficulty to learning another Slavic language if you already speak one.

Also, the written part is not hard - if you pause enough most Slavic language menus at a restaurant for example can be understood. It’s the spoken version that often makes it hard to communicate across these languages.

[eequah9L]

... and my experience is that even fairly similar languages are really hard to understand. I have no problem talking in Russian, I understand Slovak and Czech is my mother tongue, but Ukrainian is still fairly opaque to me. I suspect any spoken intermediate language will just do the same. A soup of words of which I'll understand every second and struggle to make sense of.