If you come to this country to stay, English should be a requirement. At least some effort. This is helpful to immigrants as well - I was in a pharmacy in Miami, and everyone there only spoke Spanish. No one spoke my Dutch. It would’ve been helpful if someone spoke English, a language I happen to also speak.
There are some neighborhoods in some American cities where most of the people speak Spanish better than English. It would make good business sense for store owners in those neighborhoods (particularly for places like convenience stores) to make sure there’s always someone working there at any particular time who can speak Spanish. That doesn’t mean that everyone working there at that time should have to speak Spanish. Where’s the store you’re working at?
You should have one of the Spanish-speaking employees teach you to say something like “I’m sorry, but I don’t speak Spanish. I’ll get someone who does if you’d like” in reasonably good Spanish. That’s all that they should expect of you. If you live somewhere in the U.S. where virtually no one speaks acceptable English, it might make sense to do better, but I think that in the circumstances that you’re talking about, it’s acceptable for you to find a Spanish-speaking employee when necessary.
Again, as I commented on your OP, it’s not true that 85% of the world can speak English. 400 million speak it as their first language, 400 to 500 million more speak it reasonably well, and another one billion can speak it a little. So less than 30% of the world can speak it at all.
We expect high school students to learn something about world cultures and the structure of language itself by taking foreign language classes, but surely it’s a tiny minority of people who actually achieve fluency. Even in Spanish, which is easy, and usually taught in a form (Mexican Spanish) that has immediate value in communicating with a country that borders the U.S., not to mention millions of people on this side of the border. When it comes to “teaching Chinese” you would have to basically admit that it’s for self-enrichment only – there’s too many Chinese languages and it takes too long to learn one, to expect anyone who isn’t majoring in it at the college level to really be able to have a conversation with a native speaker. Japanese is another language that is taught pointlessly; Japanese people who actually do business with the U.S. speak English, and the classes are full of people who just want to talk about anime and will never be serious about learning to communicate.
Having had formal language immersion training in two other languages, I can assert that you learn a language primarily by listening and repetition, much like a 2-year old. A native speaker doesn’t have to be able to read in order to teach his language to another, although it certainly helps.
My children were learning to speak french before they were reading. We were warned that if they went into French immersion, we should not teach them to read English (but my 4 yo son went and did it anyway and was reading to his sister when he was 5 and she was 6 1/2). Of course you can learn a language before you can read.
My DIL was required to spend a summer in Spanish immersion before she could take up her residency. And she said that about half her patients didn’t really know enough English to deal with in medical situations. And this was not somewhere in the SW, but in Lawrence, Mass.
The idea that someone can’t learn a second language before learning to read in their first language is related to the strange notion that the written language comes first and the spoken language is a mere side effect, which a lot of people seem to at least unconsciously believe. On the contrary, the spoken language is the primary thing and the written language a later outgrowth. Language was spoken by humans for at least 100,000 years before it was written. Of the 100 billion humans who have ever lived, well over half of them couldn’t read, and yet they spoke just fine. About half the people in the world today speak at least two languages with near-native fluency.
A lot of Americans think that speaking two languages natively is something really strange because they live in a country where in the vast majority of the country it’s possible to never have to know anything except English. The ones who have to take a little bit of another language in school often assume that learning a second language must be something that takes a long time and will never result in real fluency. They often look down on people who speak another language than English at home and assume that speaking two languages means that you will be bad at one of them. This isn’t true. Speaking two languages is very normal. I’m told that any child of normal intelligence, if they grow up speaking just one language to three people who raise them, the language being different for each of those three people, they will grow up to speak those three languages with native fluency. (I.e., if they speak language A to person X, language B to person Y, and language C to person Z and they talk to those three people every day from birth, they will grow up to be native speakers of A, B, and C.)
There’s people who can speak four or five languages, but read none. You’re assuming that “read” is a requisite part of “know a language”.
America does not have an official language, and no one is required know any language. That being said, English is the primary language in use here and if you refuse to learn it then you have no one but yourself to blame for your inability to communicate.