Having a locale-aware application starting up for a locale without translation, which behavior is best from the user experience point:
- Fall back to a supported locale (and give the user the option to select another locale as well).
- Fall back to a supported translation, and keep numbers, currencies, etc. in the user's default locale.
In other words: should the format of numbers, currencies, etc. follow the user's locale even if there is no translation available?
Example: Consider an application, in en-US, displaying "1,000.00 units". The application is now started on a device whose default locale is de-DE.
The correct translation would be "1.000,00 Einheiten" - but assume the application has not been translated into German, so "Einheiten" is unknown. Should the application now rather display "1,000.00 units" or "1.000,00 units"?