NSDateFormatter: Only show localized dates if app is localized for the language
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I'm currently writing an app for the iPhone that heavily works with dates. I'm using `NSDateFormatter` to convert dates to strings. Conveniently, `NSDateFormatter` automatically creates strings in the user's language based on the region format.
Because I can't localize my app in all possible languages and regions, the app is only localized in English, German, Spanish and a few others.

When the app is running for a French user for example, the app defaults to English. That is fine, but the dates will still be converted using the French language. This results in strings like "Month: Juillet" instead of "Month: July".

How can I make the `NSDateFormatter` always use the language the app runs in?
I know that I could use `NSLocalizedString()` to localize `NSLocale` identifiers, but this will yield in incorrect region settings.

When the user usually uses a "en_GB" region and my app is localized for English in general, I want the `NSDateFormatter` to use "en_GB" and not just "en" or "en_US". When the user runs French, I want the locale to be "en" and if he runs the app in the "de_DE" region, I want the date formats to be "de_DE", too, because the app supports German.

Regards,
Fabian