Actually most people in Catalunya (Cataluña) which is Barcelona, Girona (Gerona), Lleida (Lerida) and Tarragona speaks Catalonian and usually they don’t like people of the same ‘country’ who don’t speak Catalonian!
Yes, Castilian (castellano) is the official language, but also are Catalán, Gallego and Vasco. As you know Spain has it economy based (mostly) in tourist trade so a lot of tourists come every year. Lots of them learn some Castilian (which is supposed to be the official language) before travel and… they got lost because a few percent of the Spain population speaks ‘unadulterated’ Castilian although everybody know it.
In Latin America everybody speaks some kind of Castilian, no more. (Except Paraguay where Guaraní language is also official)
I can imagine your annoyance hearing several accents and idioms, especially in technical and/or technological terms.
In my opinion English language is the easiest one even using a sort of “Shakespeare Mode”. In spite of that for some guys (like me:() it takes a looong time to express with perfection due -in part- to the geographical zone.
And believe me, the most difficult accent to understand is the Argentinean one (Capital Federal and Buenos Aires) not only because verb conjugation but the speed.
In addition and as an anecdote I had the opportunity to see/hear an Argentine and a Cuban (both cable & Internet technicians) speaking/discussing/yelling while working, and in several occasions they did not understand each other. It’s usual unless they live in US for several months or even years.


>I was in Spain (Casa Del Sol, Madrid, and Barcelona) in the early 80s and I must say those in Barcelona were the easiest to understand of all Spanish speakers I've encountered except they were not Castilian but Catalonian I think. However, I thought that Castilian was the official language of Spain? I must admit my ignorance on this as it has been too many years. Chileans were by far the most difficult to understand (even though Puerto Ricans speak the fastest). When I was attending the Defense Language Institute in Monterrey, CA (years ago) I had instructors from Argentina, Bolivia, Puerto Rico, Mexico, Chile, Spain, El Salvador, and Nicaragua. It was very confusing at times because they all insisted they spoke 'correct Spanish!' However, when I graduated, most admitted that they each at times had difficulty understanding each other :o) The most difficult part was actually learning military, medical, and technological terms. Most of my instructors did not even know the words
>because they were not in common use. And they say English is difficult! :o)