Force the translation to a defined language. (I use this function to force the fallback language to Italian. I didn't find a way to make NSLocalizedString work with italian as fallback. your comments/suggestions are welcome :) )

[Localization]ForceFallbackLanguage.m

NSString * L(NSString * translation_key, NSString * lang) {
    
    NSString * s = NSLocalizedString(translation_key, nil);
    
    // Force translation as "Lang" language if no translations are found
    if ([s isEqualToString:translation_key]) {
        NSString * path = [[NSBundle mainBundle] pathForResource:lang ofType:@"lproj"];
        NSBundle * languageBundle = [NSBundle bundleWithPath:path];
        s = [languageBundle localizedStringForKey:translation_key value:@"" table:nil];
    }
    
    return s;
}