I'm constantly amazed at how far I can get in Portugal or Italy speaking only Spanish. They're different languages but you can make it work well enough in pretty much every situation I've been in.
I recall reading an autobiography by US Supreme Court justice Sonia Sotomayor. She used to represent Fendi, the Italian fashion brand, when there were suing for copyright infringement (counterfeit goods). She would speak Spanish and the Fendi senior execs would speak Italian and they understood each other well enough. That was a real a-ha moment for me!
My grandmother had this experience when she was still alive. While waiting for us to shop for stuff at the mall, she struck up a conversation with an older Italian lady. She only knew Italian; my grandmother only knew Spanish. They made it work!