What exactly do you mean by "spanish layout"?

You don't have to do anything with the regional settings.

The only thing (just tried and verified) you need to do is installing a spanish KEYBOARD LAYOUT under "system settings" -> "region and language options" -> "languages" -> "details" (tranlated from German, I don't have an English system)

Then, you can switch through various keyboard layouts installed on your system by pressing ALT + LSHIFT.