The city state was a definable entity, though there must have been many variations of it. One rather important modern state has no language whatever of its own but contains three other languages: Switzerland.
If "Nation" is a purely ideological construct, then whatever definition we come up with will have numerous exceptions -- radical exceptions even. Shakespeare was either a strong nationalist or he meant John of Gaunt's speech on "this sceptered isle" to be taken with a grain of salt. Two visiting professors at Michigan back in the late '50s, one a poet and the other a Persian scholar there to inaugurate a Persian department were quite sentimental about "their England"; I can vaguely remember the Persian professor reciting John's speech while a bit drunk! Very passionate.
Carrol