Anybody here who comments his/her code in his native language?
I do. 100% variable names and comments in my native language. Unless I have concrete plans to share the code with the world, in that case I go for 100% English.
How do you deal with the jargon and what are the benefits of using your native language, apart from being able to type TL;DR-size comments with ease?
It's a big advantage that third-party libraries and my own code use different languages. It means my code and other code stands apart, without any conscious effort needed, which is valuable because what I do with it is so very different: my own code is mallable and subject to refactorings, whereas the names in third-party libraries are fixed externalities. Say for example I have a method name "afslut" - I can search/replace that to "luk" in an instant, because I know that "afslut" means what I've chosen it to mean and nothing else. If I had called it "close" instead, I would have had to worry about all the libraries I use that also use the name "close". And I can use names such as "hvis" and "indtil" freely, because they're not keywords, unlike "if" and "while".
And now that you mention it, the ease of writing comments is another advantage. I write long comments and maintain them. You know how people say that all comments are lies? Well, they're not. Maybe theirs are. Mine aren't.
I'm always getting flack for my choice, from people who have never tried using their own language for programming. Thank you for asking before judging. You have no idea how rare that is.