Can you get by everywhere in the Americas with just four languages?

Yes, I agree with that. But the OP’s requirement for language seem to be just to “get by”, it would be a stretch to say English is not enough to “get by” in the U.S. So even though there are non-Spanish speakers in Mexico, Spanish should be more than enough to get by.
I’m assuming “get by” as being able to ask for directions, order food, checking in hotels, read signs etc…

You would never go to the places in the U.S. where people speak French or German. They’re rural, poor, and have no business connections to the outside world. The parts of Mexico and Peru where Spanish isn’t spoken are pretty much the same.

The other languages are spoken in enclaves in cities. There are certainly individual blocks in New York or 20 other cities where you’re out of luck if all you speak is English, but you can just walk to the next block.

ETA: my point was made by a previous poster.

The OP asked two related but not-exactly-the-same questions in the OP. He asked if you could “get by” everywhere in the Americas with one of the four major languages, and whether there were places where “significant numbers” of people don’t speak one of them. I would imagine that even in most places where most people aren’t fluent in one of them, you could still “get by” in that you could find a few individuals who spoke an outside language, or at least people would know enough so you could get food, ask directions, etc.

Are Haitian Creole and French unintelligible in both directions? Jamaicans speak an English Creole that many non-Jamaicans find difficult to understand, but they are perfectly capable of understanding English and most are able to speak it. Do most Haitians speak and understand only Creole?

I’m still calling bullshit on your claim that there are “substantial populations of monolingual Francophones in Maine and Louisiana, and members of Pennsylvania and Ohio’s rural religious communities who speak only 17th-century German”. Emphasis added.

I don’t really care if you have a different definition of “substantial” than I do, but there are communities in the rural areas of those states where French is the daily language and, especially among the older people, there was no impetus or access to formally study a second language and become fluent in English. There are also hundreds of thousands of fresh off the boat Haitians and West Africans in the U.S. who don’t speak anything but French, yet.

I have to agree. It is hard to find substantial numbers of monolingual francophones along the southern border of Quebec, the part known as the Eastern Townships. Although the provincial government is working its damndest to wipe out bilingualism.

I read a news story a couple years ago about a Mexican family in Los Angeles … I don’t recall if the family was from Oaxaca (many of my Mexican friends way up here in Washington state originate in Oaxaca), but the main thrust of the story was that the family was from a very isolated rural community in Mexico where they spoke their native language instead of Español. The father in the family had basically sold his 13-year-old daughter to be the wife of an older man, in exchange for a goat. Apparently, this was a normal thing amongst their particular culture. The problem was that that kind of thing isn’t acceptable in the USA. The main thrust of the story was that there were no court interpreters who spoke this family’s language. (IIRC, the situation was resolved, the “contract” voided, and the girl was returned to her family after they finally found an interpreter to explain, “You can’t do that here.”)

My experience Spanish is understood in nearly any public transaction or interaction one would have in southern Mexico as a tourist or traveler in any thoroughfare. However, if one went into a household or very isolated village, it may be different. But monolingual indigenous areas are monolingual in part as they are inaccessible to most outsiders, including Mexicans.

It is often the case that the men in these communities are bilingual, from work and contact with outsiders, but women are not. This is also true in Tarahumara areas of Chihuahua that are not too far from the U.S. border.

Parts of the Bolivian or Peruvian highlands may be different, but I have never been.

And while my sense is that in the Netherlands, English is widely understood, is this true of Dutch-speaking Americas? I think Papiamento is the main language there, which suggests Spanish/Portuguese may be a more useful language.

The singer from my current favorite band is Dutch, but she speaks perfect English. With an American accent.

My favorite baseball team, the Seattle Mariners, has had a couple players from Curaçao, and they have spoken English quite fluently. It probably helps that English is pretty damned similar to Dutch.

No, not in my experience. As a francophone I had not any great trouble in Haïti. Persons who have completed the elementary education - which is the 60% of the population at least - have at least the basic French and can understand the French well enough, and much French is mixed into the Kreyol. The pure Kreyol is not understandable to the French speaker easily, but the population has enough constant exposure to the French that the understanding of the ordinary daily French is okay.

Not really, not for most of the purposes. Only perhaps in the most back country places do you have trouble. the basic education is almost always in the French and the Haïtiens - anyone with the radio or other media are exposed to much French.

Of course to understand their own speech in the true Kreyol, no one can not really. It is very different.

I grew up in Northern Vermont and Maine. There are some French mono-glots in those areas, but even in very rural communities 20+ years ago they were pretty rare (and almost exclusively, pretty old). So at least in that region, I don’t think its correct to say there are substantial numbers of French -only speakers, even way out in the sticks. Maybe a generation or two ago that would’ve been true.

You could probably get by pretty well with zero languages, at least in any place a tourist would be likely to go. Heinlein wrote, about his trip around the world, that he had a lot easier time communicating with the locals in Brazil, with no language in common, than in Tristan del Cunha, where everyone speaks English, just because of cultural differences.

For my job I often work with Haitian DHS parolees awaiting adjudication of their cases here in California, and my colleague, who’s French, has determined that much fewer than 60% really understand French, and fewer than that can speak it. They SAY they can understand French, to save face, (because they know that in school they were “supposed” to learn it) but in practice their understanding is insufficient, at least for our purposes, and so we must work with Creole interpreters. She says that maybe about one in four can effectively communicate in French.

This being GQ, then, you can provide us with a cite of just how many of these people are monoglot French or German? Because, we all have opinions, but we don’t necessarily all have the facts.

Which has nothing to do with Mainiacs or Cajuns. That is the claim I am calling bullshit on.