Asking "What nationality are you" seems to be an American social game. But is it really a relevant question? When people ask me this, I answer, "I'm American." How can I be anything else?
Three of my grandparents were born in the U.S. and one in a part of Germany now in Poland. I hardly knew my German-born grandmother when I was growing up. I certainly was not German when I went to Germany.
Four of my great-grandparents were born in Germany. See above. I never met any of them. Three of my great-grandparents were born in England. I only knew one of my great-grandmothers and about the only English custom observed when we visited her was drinking tea, with Carnation milk! I certainly was not English when I went to England.
One of my great-grandfathers, the one with the "Irish" name, was born in Williamsburgh, New York, now a neighborhood of Brooklyn. I never knew him, and I only drove through Brooklyn to get to JFK. I doubt anybody anywhere would consider me a Brooklynite.
I've known several people who've called themselves Swedish or Italian, but I bet I've spent more time in those countries and know more of both languages than many of these people's parents. Not all by any means, but enough to wonder why these people call themselves Swedish or Italian rather than Americans.
Ironically, Americans often consider Canadian, Australian, and New Zealander as nationalities. But these countries are populated with people from all over the world, just like the United States.
Even more ironically, many of the "nationalities" represent nation-states that are themselves made of people with ancestors outside the borders of the nation states. Consider the often beleaguered nation Poland. Most of the people there have German, Swedish, Finnish, Russian, Latvian, and other ancestors. The French skier, Jean-Claude Killey's grandfather was a Kelly. And what nationality is the president of France, Nicolas Sarkozy? According to American custom he is Hungarian-Greek-Jewish-Spanish-… Are there any French "birthers" demanding to see Sarkozy's birth certificate?