Buying an XBOX One in Spain but want to play games in English

you can set your region to englisch and everything will be in english... provided the game itself is multi language which so far like 98% have been to my knowledge. I live in germany and do the same.

Most games also offer language selection in game (like Dragon Age, Witcher, Fifa, etc.)

You are good to go.  As Xbox One is "Region Free"

After you get set up on Xbox One, just go to settings and change the language to English and still have Spain set as your country on Xbox One.

Currently it's not possible to set the location to "Spain" and the language to "English".

The locations that are available for "Espanol" are Argentina, Chile, Colombia, Espana and Mexico.

The locations that are available for "English" are Australia, Canada, Czech Republic, Greece, Hong Kong, Hungary, India, Ireland, Israel, New Zealand, Saudi Arabia, Singapore, Slovakia, South Africa, UAE, United Kingdom and the United States.

Some games like Battlefield 4 or The Witcher 3 offer to change the language in-game, if your preferred language is available. Depends on the game.

Okay, didn't know that Spain users cannot use another language right now, I hope Microsoft does a patch to have your preferred language no matter what territory you're at. Like for example, if you live in Sweden, then Swedish language is the only language available.

Never understood (since DVD),why i can choose several languages & subtitles to watch a movie.But it's not possible for games (just a few)....

And it's not related to devices but more on what the devs includes on the disc....Seems most of them doesn't care to include this option.