But one thing that strikes me on New England is that the entire region seems to have its own unique sort of culture, very different from that of New York, New Jersey, Philly, Chicago or Detroit. Both Italians and Irish seem to have blended into that kind of New England atmosphere.
I don't know about New England, but I think what you say applies to most places. Italian Americans are totally assimilated into American culture. There are very few actual Italian neighborhoods, none of us speak a word of Italian. And most of us that would identify as Italian probably are also Irish, if not also several other European ancestries.
