"We are American" or "We are Americans"? The singular vs. the plural form? [duplicate]

Which expression is more idiomatic or correct:

• We are American
• We are Americans

Should I use American in the singular or in the plural form? And why?

Solution 1:

You can virtually force one version or the other by context:

Are you Americans or Canadians? ...

Are you Canadian? ...

I don't think RyeɃreḁd's answer will really stand much scrutiny, though doubtless there are factors nudging one's choice one way or the other. And it is a choice:

We are American / I am American

'American' here is a (proper) adjective; compare 'We are cold'. It has no 'plural form'.

We are Americans / I am an American

'Americans' and 'American' here are proper nouns; compare 'We are doctors'.

An Ngram shows that both constructions are commonly used. But you wouldn't get many Brits, standing in a defined group of people or otherwise, volunteering 'We are Britons' / 'Englishmen'. 'We are British' / 'English' is the far more usual way of putting this (as further Ngrams illustrate).

Solution 2:

You would say "We are Americans" if you are standing in a defined group of people (can be counted) and talking about your group as individuals.

You would say "We are American" if talking about an abstract uncountable population or a group of people that will stay grouped.

Usage:

Going through customs with your family, you are asked "What nationality are each of you?" Answer, "We are Americans."

Person in a foreign country asks, "Is the new group of doctors from the U.S. or Canada?" Answer, "We are American."