I worked for a company that had Spanish speakers from Mexico, Peru, El Salvador, and Argentina, to name a few countires of origin. Then an assistant HR manager from Spain was added to the mix. There were definite dialect issues, especially when the HR person did translations.
I did take a 6-week conversational Spanish course given by the company. I asked the teacher (Puerto Rican lady) for words to avoid. She said it would be impossible to tell me all of them in all the different dialects. Her job was to teach very basic words that were common to all (body parts, asking for help, etc.). Sadly, it didn't stick too well.