Language detection in iOS. This code is used to add the language to a post in my ADN client hAppy. This is pubic domain. To with it what every you like!

DDHLanguageDetection.m

NSString *languageGuessedString;
    
if (postString.length < 60) {
  languageGuessedString = nil;
} else {
  NSArray *componentsArray = [postString componentsSeparatedByString:@" "];
  NSMutableString *mutablePostString = [NSMutableString string];
  for (NSString *string in componentsArray) {
    if ([string rangeOfString:@"@"].location != NSNotFound) {
      continue;
    }
    NSDataDetector *detector = [NSDataDetector dataDetectorWithTypes:NSTextCheckingTypeLink error:nil];
    NSUInteger numberOfMatches = [detector numberOfMatchesInString:string options:0 range:NSMakeRange(0, string.length)];
    if (numberOfMatches > 0) {
      continue;
    }
            
    [mutablePostString appendFormat:@"%@ ", string];
  }
  languageGuessedString = (NSString*)CFBridgingRelease(CFStringTokenizerCopyBestStringLanguage((CFStringRef)mutablePostString, CFRangeMake(0, mutablePostString.length)));
}
NSLog(@"languageGuessedString: %@", languageGuessedString);

NSString *primaryLanguage;
if (languageGuessedString) {
  primaryLanguage = languageGuessedString;
} else {
  primaryLanguage = [UITextInputMode currentInputMode].primaryLanguage;
}

NSString *languageString;
if ([primaryLanguage isEqualToString:@"zh-Hant"]) {
  languageString = @"zh_CN";
} else if ([primaryLanguage isEqualToString:@"zh-Hans"]) {
  languageString = @"zh_TW";
} else {
  languageString = [[primaryLanguage componentsSeparatedByString:@"-"] objectAtIndex:0];
}
NSLog(@">>>> set language: %@", languageString);