"I'll just pick it up while I'm there" sounds like you didn't pack a beach towel and plan on getting one when you arrive at the beach,not learning an entire new language.
Maybe I should have ridden the short bus, (not that we had buses,we walked to school, but I digress), cuz, I just don't get it. How do people manage to just pick up a new language? I understand that kids can, and do. Kids are sponges. I am enchanted by our little Canadian friend, she is 8 years old and in a year is as fluent in her use of the Spanish language as any other 8 year old. I find her Yucatecan accent charming, in fact, it cracks me up to hear her say "pam" instead of "pan" (Yucatecans are notorious for saying m instead of n, so you hear Yucatam not Yucatan all the time, pam not pan when they want bread). She of course, is surrounded by Yucatecos, her best friend is a Yucateca and so are all her schoolmates. Her parents invested in additional tutoring for her so she would be at grade level in her reading and writing too. She is totally immersed, in fact, I think besides her parents we are the only native English speakers she knows, though she speaks Spanish to us too, it doesn't occur to her to speak English.
How do people live here who don't speak Spanish? What does it feel like? To constantly be surrounded by words that you don't understand, writing that you can't read? Why do people chose to do that? I understand if you are coming for a vacation, but to live your life here?
I wonder if it's because as Americans we are surrounded by English, unlike Europeans who sometimes live in countries who have more than one language or are within driving distance of a couple of different countries. We don't understand the mechanics of learning a new language.
While, I haven't done a survey, or any real research, I think the number one question people ask is "Do I have to speak Spanish to live in Mérida?". The answer is no, but it will be frustrating. If you want to preview what living in a foreign country without speaking the language is like;
spend the day not talking, only communicating by using pantomime and pointing. If you are really brave try grocery shopping without reading any signs or labels , buy canned goods and packaged by what you think the graphics represent. If you don't have kids, go down the baby food aisle and see what you might have bought if you couldn't read. That is what l think living in Mexico without speaking Spanish must be like.
I was shopping with a girlfriend, we stopped to look at the refrigerators. I commented that I wanted a larger one but all them had unacceptable efficiency ratings. I commented that we paid extra for our little Sanyo refrigerator because it is supposed to be in the 30% efficiency rating (70% of all similar frigs are more efficient).It was the most efficient model available. While we were talking, it dawned on my poor friend that she had just bought the least efficient model available!
I asked her what it was like not speaking Spanish, she said "Sometimes it's just hell."