In Chinatown on Manhattan, there are areas like that (though I suppose the senior citizens mostly speak Cantonese there). Many of the store signboards are in Chinese only, and inside, the labels may also be only in Chinese; then only the fact that I still remember a bunch of kanji allows me to tell a duck from a chicken, when both are wrapped in impenetrable dark plastic.
Yeah I know the area. My wife and I have been through there a few times (she is from Taiwan). Lots of people who barely speak any English at all, but you might not know if you didn’t speak Chinese.
That kindly old man making noodles behind the counter on that restaurant you frequent off Canal St? The one that always has a stoic face and never says a word? He doesn’t speak any English, but try chatting with him in Mandarin and he’ll talk your ear off with his life story.