You can do something like this:
NSString *bundlePath = [[NSBundle mainBundle] pathForResource:@"Localizable" ofType:@"strings" inDirectory:nil forLocalization:@"es"];
NSBundle *spanishBundle = [[NSBundle alloc] initWithPath:[bundlePath stringByDeletingLastPathComponent]];
NSLocalizedStringFromTableInBundle(@"House", nil, spanishBundle, nil):