Ten generations, sure - there we're talking about those who are descended from before the big 1880-1920 wave of immigration. But from then on it gets different. Perhaps not out west where the Italians and Irish and Poles no longer have any ties to the old village-like urban enclaves, but in the Northeast and the metropolitan areas of the industrial Midwest things are different. Here you get fourth generation Italian kids going wild over Italy's soccer team, waving their flags as they run through the streets. Kids who don't follow soccer, have never been to Italy, and don't speak any Italian - but they sure as hell are Italian, and Italy won.
This town is a mosaic of tribes and sub-tribes for whom their ethnic identity is an essential part of both their intense local identity and their national (American) one. Even when they move out into the suburbs they retain their ethnic identities, thus giving us phenomena like Congressman Peter King (R/Sinn Fein-NY) whose Irish Republican allegiance takes precedence over his US Republican one.
The new immigrants here have been replicating the same pattern - settling in concentrated groups, filling their neighbourhoods with markers of the old country - all as part of the process of assimilation. My impression is that this is also true of Latino and Asian immigrants in California.
Kohn suffers from a guilty conscience, because he had a fallout with Grün and feels it was his own fault. So he goes to the rabbi, tells him the story and asks for advice. "You have to say sorry!" "Do I really have to say sorry?" "Definitely." "Can I also do it on the telephone?" "Yes." Hearing this, Kohn goes home and dials Grün's number. The other end of the line answers: "Hallo?" "Hallo... is that Mr. Smith?" "No, I1m Mr. Grün." "Then sorry." *Lunatic*, n. One whose delusions are out of fashion.
I guess my experience in Chicago and California is that these enclaves break down over a generation or two. The German area in Chicago I believe is now Latino, with people moving out to the suburbs, or just marrying and moving. In California I live in an area that is 40% Asian (lots of countries when I say Asian) and 60% everything else. However the various China town areas do seem to maintain their Asian roots--but some of that seems business related. Like in that area in London just south of Soho,,,very Chinese/Asian it would seem, and everyone knows where to go to get various varieties of Chinese food.