The struggle with thoughts about writing stories in foreign languages

From time to time, I find myself wondering if I could write a story in English. My grammar is okay and I know how to use a dictionary. Furthermore I've been working as a professional author for around eight years now, having typed millions of characters on virtual white sheets. I know how to develop a solid concept for a story. Therefore it can't be too difficult to write something equally nice in a foreign language, can it?

From my point of view I'm lacking a sense of humour. In German, my native tongue, I would say that I'm "humorbefreit" (freed from humour) because I like that it sounds as if someone had stolen my sense of humour. What a relief! However, many readers find my stories funny, although the majority of "jokes" were not intended.

Since I obviously produce funny situations by pure chance, couldn't I do the same in English?

Then I remember that grammar and dictionaries don't make a story readable. Or rather: worthwhile reading.

I often use images and allusions rooted in my Western/European/German/regional culture/society/education and sometimes even puns. Those things often can't be conveyed into another language that easily. (or say "Those things aren't easily conveyed into another language.")

So if I wanted to write (and sell!) a story in English, I would not only need a good knowledge of grammar and a big dictionary, but also a fine sense of the culture of my readership. However, where should the latter come from when I never go abroad?  (Although people do it all the time, grammatically one should not use the conjunction "but" at the beginning of a sentence.)

Your English is damn near perfect. Here is all that I found was wrong, or could be changed to sound more natural! I'd be surprised if you weren't C2 level (at least at writing)

For  From (or as for) my point of view, I'm lacking a sense of humour. In German, my native tongue, I would say that I'm "humorbefreit" (freed from humour) because I like that it sounds as if though someone had stolen my sense of humour. What a relief! However, many readers find my stories funny although the majority of "jokes" were not intended.

Since I obviously produce funny situations by pure chance*, couldn't I do the same in English?

Then I remember that grammar and dictionaries don't make a story readable. Or rather: worthwhile reading.

I often use images and allusions rooted in my Western/European/German/regional culture/society/education – and sometimes even puns. Those things often can't be conveyed into another language that easily.

So if I wanted to write (and sell!) a story in English, I would not only need a good knowledge on grammar and a big dictionary, but also a fine sense for the culture of my readership. But where should the latter come from when I never go abroad?

* I would write 'purely by chance' but I don't think that's wrong. 

Fantastic writing, I think you should definitely try and write something in English. Just get it proofread by a native speaker after, and I'm sure it will be fine. 

Maybe if you really wanted, you could spend some time in the UK to get that culture sense. But I think you are definitely ready!