Search for "region" in the start menu and click the one showing up (Region & Language).
If your Windows locale is already in Spanish, my Spanish knowledge is a bit limited on how to get to them, especially the second setting. It should be on the middle of the Region and Language panel.
Now that I think of it, there is actually an annoying "feature" in Windows that automagically adds languages based on how you use your PC. Which language apps you use and such. Those settings are only accessible on the old-school full control panel, under that one's Language settings. To open the old-school full control panel, search for Control Panel in the start menu and then click "Clock, Language and Region" and then click "Language". On the Language panel, click even deeper on the Advanced option on the left hand column.
I do experience something similar to your problem from time to time, because Windows apparently thinks my Irish keyboard isn't American enough, so it sometimes adds US-EN as an option. That feature is supposedly the one called "Let me set a different input method for each app windows", on that Advanced page on the Language control panel. For clarification, this is still that full Language control panel and not the Windows 10 styled Language & Region panel. For additional clarification, this particular setting seems to be extremely hit or miss. I get the feeling there's an even deeper hidden dynamic setting for keyboard options because I still get the occasional dynamically added keyboard option on my PC. I haven't bothered searching for that myself, as that would probably be hidden somewhere in the Windows Registry.
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