结果如下:

- (NSString *)languageForString:(NSString *) text{

     if (text.length < 100) {
         return (NSString *) CFStringTokenizerCopyBestStringLanguage((CFStringRef)text, CFRangeMake(0, text.length));
     } else {
         return (NSString *)CFStringTokenizerCopyBestStringLanguage((CFStringRef)text, CFRangeMake(0, 100));
     }
}