Should you use international identifiers in Java/C#?

I used to work in a development team that happily wiped their asses with any naming (and for that matter any other coding) conventions. Believe it or not, having to cope with ä's and ö's in the code was a contributing factor of me resigning. Though I'm Finnish, I prefer writing code with US keyboard settings because curly and square brackets are a pain to write in a Finnish keyboard (try right alt and 7 and 0 for curlies).

So I say stick with the ascii characters.

I'd say it entirely depends on who's working on the codebase.

If you have a small group of developers who all share a common language and you don't ever plan needing anyone who doesn't speak the language to work on the code then go ahead and use whatever characters you want.

If you need to have people of varying cultures and languages working on the code then it's probably best to stick with English since it's the common denominator for just about everyone in the world.

I would stick to english, simply because you usually never know who is working on that code, and because some third-party tools used in the build/testing/bugtracking progress may have problems. Typing äöüß on a Non-German Keyboard is simply a PITA, and I simply believe that anyone involved in software development should speak english, but maybe that's just my arrogance as a non-native-english speaker.

What you call "American arrogance" is not whether or not your program uses international variable names, it's when your program thinks "Währung" and "Wahrung" are the same words.

If your business are non-English speakers, and you think Domain Driven Design has something to it, then there is another aspect: How do we, as developers, use the same domain language as our business without any translation overhead?

That does not only mean translations between languages, say English and Norwegian, but also between different words. We should use the exact same words as our business for our entity classes and services.

I have found it easier to just give in and use my native language. Now that my code use the same words, it's easier to have a conversation with my domain experts. And after a while you get used to it, just like how you got used to code without Hungarian notation.