решил свой вопрос!
NSString *language = [[NSLocale preferredLanguages] firstObject];
if (!language) {
language = @"en";
}
NSLog(@"The device's specified language is %@", language);
Swift версия:
var language : String! = "en"
if let lng = NSLocale.preferredLanguages().first {
language = lng
}
print("The device's specified language is \(language)")