Step 1. Local info Apple Doc:

https://developer.apple.com/library/mac/#documentation/MacOSX/Conceptual/BPInternational/Articles/LanguageDesignations.html#//apple_ref/doc/uid/20002144-BBCEGGFF

Step 2.

//For Buzztouch 2.0

Add to: yourappsdelegate_appDelegate.h

//For Buzztouch 3.0

Added to: BT_loadConfigDataViewController.h

NSMutableArray *langCodes;
NSMutableArray *langNames;


@property (nonatomic, retain) NSMutableArray *langCodes;
@property (nonatomic, retain) NSMutableArray *langNames;



Step 3. 

//For Buzztouch 2.0

Add to: yourappsdelegate_appDelegate.m

//For Buzztouch 3.0

Add to: BT_loadConfigDataViewController.m


@synthesize langCodes, langNames;


// list of languages
   
   
   //int language arrays
   self.langCodes = [[NSMutableArray alloc] init];
   self.langNames = [[NSMutableArray alloc] init];
   
   //fill up the language codes
   [langCodes addObject:@"en"];
   [langCodes addObject:@"es"];
   
    
   //fill up the language names
   [langNames addObject:@"English"];
   [langNames addObject:@"Spanish"];

   //determine the language
   
   NSString *language = [[NSLocale preferredLanguages] objectAtIndex:0];
   NSLog(@"##### %@", language);


Step 4.


  //build the name of the language file
  NSString *languageFileName = [NSString stringWithFormat:@"BT_config_%@.txt", language];
  
  //does this file exist?
  if ([BT_fileManager doesFileExistInBundle:languageFileName]) {
      configurationFileName = languageFileName;
  
  }

Resources

Buzztouch Localization Video Part 2 - Minute 8


https://www.youtube.com/watch?v=BcZ485Wp80s