you learn "castillian" or "castillano" spanish. It's a very proper form of spanish, close to that used in Spain. Most people will understand you when you speak it. I got to meet 2 sisters from Madrid, and spoke with them in spanish. I understood everything they said, and they understood me quite well. TRUE, I haven't gotten far with them, and True you don't learn SPAIN spanish exactly (they have a nasty lisp), but it's excellent. I never learned any grammar, and yet, I can tell when somethings sound right or not.
my wife told me the word they use for cake in Puerto Rico means "prostitute" in Spain. I think. or the other way around. I can't remember. Safest bet is never to offer cake to a spanish speaking person.
lol, I'll keep that in mind. I wouldn't want to ask a sister if she wants cake, but accidently asking her if she's a prostitute. That does NOT go over big.