Most countries we would label as communist didn’t form as Marx expected. Marx expected relatively advanced nations to revolt and claim control over capital. Instead, most Communist revolutions occurred in generally despotic and less developed countries.
When times are good, the government can use the material improvement of people’s lives as a reason to be in power. However, if times stop being good, the government becomes more overtly autocratic to maintain control.
Within the USA, the language enclaves aren’t strong enough. You might find people who can’t speak English, but there are enough people in their communities that can speak English that you can get along.
Of the countries I’ve visited so far, I find that Mexico has the strongest language barrier as Mexico is large enough to maintain an internal standard of Mexican Spanish. Outside of the northern border states, you can drive two states away in Mexico and still have people speak Spanish.