I'm an Australian who learned Spanish in Mexico and has put it to use in Andorra, Belize, Costa Rica, El Salvador, Honduras, Guatemala, Morocco, Nicaragua, Panama, and Spain. (Yeah I know Spanish isn't official in two or three of those countries but I ended up using it anyway at least some of the time.)
Sometimes people try to tell me I'm fluent but I'm definitely not.
I have a collection of monolingual and bilingual Spanish dictionaries that I've bought, many second hand, on my travels. I always look for a dictionary of regionalisms in each Spanish speaking country. I don't always find one.