Hello Latin
You can get some information in the sites below about what you want to know,
Nationality and Language (1)
Nationality and Language (2)
Nationality and Language (3)
What I am now confused with is whether I can put "a" to a predicate noun of nationality or not.
I was taught I have to say "I'm Japanese", not "I'm a Japanese".
But they say "He is an Italian" as often as "He is Italian", as Mr P pointed out.
Does the allowance of "a" depend on nationality?
I mean if "Z-an" people are allowed to say like "I'm a Z-an" but not "Z-ese" people like "I'm a Z-ese".
paco