Very interesting concept that you introduced to us with this blog post, Jballou.
As a native French speaker, I can relate to that story. I started learning English at school in my teenage years, and what I learned there was scholar and academic. When I went to university, I spent some time watching TV and movies in English (mostly US English), which improved my skills, to the point where I became fluent or nearly fluent.
But when I talk to someone in English, and more particularly when I write in English like I’m doing now (because I can take the time to check what I’ve written and ponder wether every word was correct and relevant), I have the constant fear of sounding or looking awkward. After all, because I learned a phrase in a Kurt Russel movie doesn’t mean it’s ok to use it on a web forum in a discussion about politics. And even in casual conversation, the punch lines I learned in 80’s movies could have been “da bomb” back in these days, but could sound terribly dated today.
So, yes, when I express myself in English, I’m almost always wondering if my speech sounds as coherent and wise as it would sound in French, or if I just sound like some hardly intelligible moron.