initwithnibname总是加载英文xib

我有一个本地化的aboutapp.xib文件,其中包含英语和ES本地化版本,但即使我将手机的语言设置为西班牙语,它也始终加载英语版本。如何根据语言加载西班牙语版本?

// Make sure AboutApp View is allocated
if (self.aboutAppController == nil) {
    AboutApp* aboutApp =
        [[AboutApp alloc] initWithNibName:@"AboutApp" bundle:nil];
    self.aboutAppController = aboutApp;
    [aboutApp release];
}

[UIView beginAnimations: nil context: nil];
[UIView setAnimationDuration: 1.0f];
[UIView setAnimationTransition: UIViewAnimationTransitionCurlUp
                       forView: [self.view window] cache: YES];
[self presentModalViewController: self.aboutAppController animated: YES];
[UIView commitAnimations];