Hey, don't count Germany to etc.
I can't quite match what the guy in the blog wrote but at the base of it I've had similar experiences.
I was already pretty far with English in school when I first played Shenmue so I was able to understand most of the game right away. It still helped me getting better though. That something that just happens if you're "forced" to take the entire thing in English and when you like it, you automatically attach to it and get the best teaching you could ever have!
Years later the internet contributed a hell of a lot more to my English. All the websites, forums and especially online shows like the AVGN helped me to get better and better, way beyond what you learn in school. You just get to know the language much more "natural" that way. Similar to the guy in the blog, I don't think about grammar or verb tenses when I write something, even though I learned that stuff in school many years ago. I just write, it just flows naturally. I don't even have to think in my native language anymore and carefully transalte what I want to express. I just think in English right away.
I also have a little story with Japanese as well. Shenmue II's Japanese dub teached me a couple of words though that's about it. I can barely form sentences in Japanese and reading is even worse, let alone writing. That's because I never cared as much as I maybe should have. I never touched any other Japanese material then Shenmue II, besides the random game that has a Japanese dub where I understand certain words that I learned from Shenmue.
Oh well, hopefully it was interesting enough to read my stuff.