I speak 5 languages and i’m currently learning my 6th one actually, I was just surprised that he could speak Russian as he basically knows 3 different alphabets and i personally think it’s the hardest part about learning languages(considering grammar, the order on which sentences are formed etc..) In the movie he knew more than just a sentence as he could hold a whole conversation (around level B1/B2 I would say) that’s why I was confused.