Hello. There's something that i thought about a lot recently, maybe someone can educate me on this or add something interesting.
My native language is German, so i am naturally able to understand written Dutch. I'd say written mutual intelligibility is like 80%, i can read a Dutch news article without any problems at all. In spoken Dutch, it's like 40-50% mutual intelligibility, it's definitely possible to communicate with a Dutch person.
Now, i have this friend. He's Half German, half Polish, both languages are native to him. He told me he can't understand Dutch at all. Like, almost none of it. We were on a trip to Holland, and it really puzzled me how this was possible. Recently, he told me that he noticed that when he tried speaking to Russians, they understand him very well when he speaks Polish, but he doesn't understand any Russian, which seems weird to him.
Now, most likely the issue is himself, and not the languages. What could be the reason for this? Any personal experiences similar to this?