iOS has separate region and language settings. Quick look at Apple docs suggests that this is the former.

No, it's the latter.

In NSLocale, "region" is a subtype of language, as in a regional dialect, not an independent dimension.

https://developer.apple.com/documentation/foundation/nslocal...

https://developer.apple.com/library/archive/documentation/Ma...

Nope, [[NSLocale currentLocale] countryCode] returns Region country code from settings. The same code is also used for language region, so you can end up with something like zh_US.

I wonder if there are similar oversights with the US locale, seeing as a lot of developers prefer English interfaces to the somewhat craptastic localizations.

CN is the country code, not the language code. zh-CN is simplified chinese localized to mainland China. If you want simplified chinese try something like zh-HK or zh-SG.

But there is valid criticism to be had that Apple should be signposting more visibly the differences between its settings for CN and outside CN.

Your data is sent to Google otherwise.

...which is what I strongly prefer (rule of law and all that). Of course, as others have said, on-device processing would be the best.

Not just EU and US based users, but also Hong Kong and Taiwan based users.

Hong Kong, Macao and Taiwan all have their own ISO 3166 codes and users there are unlikely to accidentally set the region to CN, since the difference between simplified and traditional characters is quite obvious.

This sounds like the more dangerous story here. What the heck?

Google is blocked in China so naturally they'd need a Chinese alternative, with everything going on it's easy to fear monger but people need to chill out a bit. Locale is probably one of the least intrusive ways to determine location, using GPS would probably cause an even further problem if people realise that there's a backdoor to avoid location permission

Any company that markets/releases in China and relies on some google service (maps/safe search/safety net/google sign in/firebase/etc) need to find an alternative, not because everyone is on the Chinese payroll but more often than not these services are business critical.

Wouldn't the locale be set to CN for phones which are in non-china countries too?

Language and Locale are separate preferences. You can mix and match however you want on iOS.

Oh I see. That is where I got confused then.