Comment by nfc
10 hours ago
It seems like an extremely coarse classification. Category 3 contains languages with very different degrees of difficulty, while Bulgarian and Russian are both Slavic they are nothing alike in terms of difficulty since Bulgarian is the most analytic of Slavic languages (has the less inflection). That makes it extremely easy to learn compared to Russian.
What is also interesting is how written Russian was heavily influenced by old Bulgarian. In fact, written russian includes a lot of older written bulgarian vocabulary.
This results in a weird paradox: for literate Russians it is easy enough to read written bulgarian but almost impossible to understand the spoken language.
I speak Russian and some Bulgarian as third/forth languages, and while I agree that Russian is more difficult, I wouldn't say Bulgarian is "extremely easy" in comparison. It's maybe ~20% easier at best.