The Spanish/english debate has raged for years. Fact is it is ICAO, what you where taught is not relevant, the only relevant thing is the regs. It may change one day but until then is the law of the land.
I would say that it will be a tall order to join Iberia, Spanair or Air Europa if you don't speak fluent Spanish. You will not pass the selection as it is mostly in Spanish and very competitive. On top of that you may need support from the inside or so they say.
On the bright side you will need no spanish or contacts at all to join EZY, Ryan (if you can bear the thought - I can't) and Vueling.