Detect language in use by iOS application

Question

How can I detect the current application language ? I am not talking about NSLocale user preferences.

In my app there are currently two supported languages

Answer 1

I usually reserve a special key in Localizable.strings, such as "HTTPAcceptLanguage", which I set to "en", "fr", etc. Now telling your server the language displayed by the application is as simple as NSLocalizedString(@"HTTPAcceptLanguage", nil).