Hi ,
When you fly with spanish companies flight operations are done in english when outside of Spanish terretory, but when in Spain you speak in Spainsh with Ground Control and crew near always talk in spanish with each other. They ask you to be able to speack both English and Spanish top be able to be considered, and they definitley prefer you to be more fluent in spanish than in english.
Some companies such as binter only consider nationals and particularly people from canary islands, I belive Tap does the same in portugal.
Regards,
Richiya