From http://stackoverflow.com/questions/14259674/switching-between-localized-storyboard-at-runtime

switch language at runtime

 UIStoryboard *storyBoard;
 if ([language isEqualToString:@"ar"]) {
   lan = [[NSLocale preferredLanguages] objectAtIndex:0];
   storyBoard = [UIStoryboard storyboardWithName:@"MainStoryboard_iPhone5Arabic" bundle:bnd];
 }
 else if([language isEqualToString:@"en"]) {
    NSLog(@"DDD ");
    lan = [[NSLocale preferredLanguages] objectAtIndex:20];
    storyBoard = [UIStoryboard storyboardWithName:@"MainStoryboard_iPhone5English" bundle:bnd];
 }
 NSBundle *bnd = [NSBundle bundleWithPath:[[NSBundle mainBundle]pathForResource:lan ofType:@"lproj" ]];



UIViewController *initViewController = [storyBoard instantiateInitialViewController];
[self.window setRootViewController:initViewController];