Yes, but look at the last column, proportion as a percentage of the total population. That’s not very high at all. OK, not small, but not high either.
Some other countries I have lived in are much higher, which reminds me that other factors are just as important as the raw numbers.
The whole “diversity” feud, (in which I will not take sides), misses a very important point, particularly in the context of this thread that began with a question on language.
I have driven through nearly every state in the Union and every Province except Newfoundland, (haven’t made it to the Territories), and have only had to rely on my broken Dictionary/Phrasebook French on a few rare occasions in Quebec–getting away with just English even in Nouveau-Brunswick. Even Yanks who travel a lot tend to do it more by car than otherwise in the U.S., so regardless of how many nations can be encompassed by a navigator’s dividers from their home, they are much more likely to have not encountered other languages, (or other English dialects), than a European would. It would be difficult for most Europeans to drive 500 miles without crossing at least one language-delineated border. (I know about driving the length of Italy, Norway, Sweden, and Finland, but my point is still valid.)
Growing up on the Canadian border, I was familiar with a lot of linguistic differences between U.S. and Canadian speech, but people not too far from where I lived would not have encountered them.
Years ago, I was in a cubicle next to a woman who was trying to help out our subsidiary in Stratford, Ontario. They needed to get someting printed and it was going to be printed to “print class Z”. It was fortunate that I overheard the conversation and provided some translation, because she had no idea why every time she asked what print class they were using, she got the answer “zed.” Raised in Georgia, she kept thinking that they were trying to talk about some computer operator named Zedediah. (Of course, with her Peach Tree accent, I had to translate some of her terms to him, as well.)
Now that we’ve settled all of that can we move on the horribly wrong way much of the world pronounces Adidas.
Let’s not not put words in my mouth. My measure was simply in response to the implied assertion that Americans are unusual because they can experience cultural diversity within their own nation. The statistics I quoted simply show that there’s nothing exceptional about the proportion of immigrants in the United States.
Nonetheless, your China analogy doesn’t hold. Take a 100L container (A) filled with 95L of white sand, 1L of blue, red, green, orange and black. Compare this to be a 1.2L container (B) containing 200mL of white, blue, red, green, orange and black. Container (A) has a greater volume of sand of each type, but container (B) is more mixed - in other words, it is more diverse.
So what? It’s a very large country. It’s like saying 20% of the world’s supply of Louis Vuitton handbags are found in the US, therefore an American is more likely to possess a LV handbag than a French person.
Simple factual answer:
yes, the majority of Americans are probably unaware
To the OP:
Not sure if you realize this, but there are similar population sizes as your OP (around 100million) within the US that use one term or another and others may not be aware of the differences.
Here’s one example:
Why would you think everyone would know about one particular “regionalism” in the world when there are probably tens of thousands of these things?
I’m just using that stat to indicate that Americans should have a very easy time encountering a variety of other cultures here at home.
The raw numbers, in some ways, impact the variety of cultures one might encounter. If a country has only 5 million people, and has 12% immigrants it seems nearly impossible that they would have the variety of immigrants as a country with several hundred million people and the same percentage of immigrants.
Great point, being raised in New York I had no idea what pop, sweet tea, sundries, or tennis shoes were until I visited other parts of the country. (plenty of other stuff, too, I’m sure)
Right, Canada is a certainly another country but I wouldn’t go so far as to call it a ‘foreign’ country at least in comparison to the U.S. I think that is why only Mexico was used in the example above. That is what makes Canadians the biggest security threat to the U.S. in my view. They look and act just like regular people until you find out one day, maybe even years later, that they aren’t when they slip up and make a reference that only a Canadian would know or care about. Maybe you have one as a neighbor or coworker and just never realized it. They can hide in plain sight just about anywhere.
People were putting words into my mouth, so why shouldn’t I? As for your sand thing, I guess we have different definitions of cultural diversity. Your definition appears to be that all the “white sand” is the same.
And moving to New Jersey from California made me realize that going out for a slice of pie was a totally different thing out here than it was back home.
A few Canadians call it “izzard”: I have no idea why.
That’s true, except his name is actually listed in the credits as “Zed,” not Z, even though Tommy Lee Jones & Will Smith are written as K & J. So it wouldn’t be surprising if most Americans who saw that film didn’t connect his name to the letter Z.
Can we all just call it Omega and be done with it?
I first learned that Z could be pronounced zed when I was in 4th grade, in the 1960s. But it was in an American context, curiously. I was reading a juvenile novel set in early 19th-century Kentucky. A girl was learning the alphabet, and she was taught that the last letter was “zed.” She kept drawing Z over and over again, saying “I do like that zed.” Because these were country people, more or less hillbillies, the pronunciation “zed” seemed to fit. But since then it has always seemed incongruous to me that it’s British. Anyway, if the book is historically accurate, it means that Americans used to call it zed too, though this has been forgotten over the years.
I’m trying to imagine the confused looks on American concert goers who see ZZ-Top in Canada.
A quote from an old tongue-im-cheek MPSIMS thread that may be relevant: :By the 1939 Treaty of Ogdensburg, Canadians agreed to stop identifying themselves as ‘not British’ and start calling themselves ‘not Americans’." 
A little known fact was the exchange of citizens that occurred because of this treaty. Draft dodging Americans were exchanged for Canadian Geeks who drove south for the winter and got lost in translation.
On behalf of America, I’d like to graciously accept the offering of Trailer Park Boys as recompense for Bryan Adams.
People keep joking about this but that’s quite seriously how the alphabet song goes in this part of the world (minus the record scratching effect, though).
The next verse is “Now I know my ABC(s), next time won’t you sing with me?” which still rhymes. I don’t get why people seem to think having “Zed” as the last letter invalidates the whole song.
It’s not really a regionalism when pretty much everywhere except the US uses it though, is it? That’s a big like describing the metric system as a “regionalism”.
And there are a heap of “regionalisms” I’m familiar with (“Soda” vs “Pop” vs “Soft Drinks” vs “Fizzy Drinks”, for example). They’re also usually (at least IME) something that can be worked out from context (or pretty well known - I mean, I think everyone knows the various major soft drink synonyms). But people in this thread and the other one appear to be saying they had *no idea at all[/] what “Zed” was. As in, they’d never heard the term at all before reading the thread.
That’s what astounded me. Not “Yeah, I know but that’s British talk and I’m an Amurrican, dammit!”, but “Never heard that at all, ever.” I just can’t fathom how that would be possible, basically.