'Mericans.

How long does it take before an African American, an Irish American, an Italian American, a Hispanic American becomes just an American?

Americans of English heritage simply describe themselves as American - you never hear the term Anglo-American, except in the instance of someone with one British and one American parent. The irony is that none are true Americans, that being reserved for Native Americans.

The term African American is an outlier, as it describes a heritage from an entire continent, rather than a single country. That, however, isn't surprising given that at the time the African slaves were first brought to the Americas in 1619, Africa didn't comprise countries as such, but fluid, tribal areas. Slaves from several different tribes were alternately split up and lumped together again in smaller ethnic groups, having little opportunity to consolidate their indigenous cultures within their new country of residence, unlike the Irish and Italians in New York. Even their names were changed.

Only some 30m of the 300m Americans can trace their ancestry to the 16th and 17th century Founding Fathers, and even the vast majority of those can only do it through one side of their family, not both. It's a cottage industry in the USA to trace your ancestry, by whatever tenuous means, to these Founding Fathers. More often than not, it's usually based solely on have the same surname as one of the early migrants - a name that was common on this side of the Atlantic and could easily have arrived much later. Just because you have the same surname as an early migrant, it doesn't necessarily mean to say you're descended from him.

We in the UK have terms for foreign immigrants who came to live here, intermarried and enriched the culture - Romano-British, Anglo-Saxon, Anglo-Norman and Anglo-Scandinavian, British-African-Caribbean, Asian British, but we don't use them in daily discourse, except for the more recent migrants, which have not yet assumed the Anglo precursor, but probably will with time. The word foreigner has now become a dirty word in some quarters.