Es ist kein Käse / Ich esse keinen Käse
Why "It is no cheese." uses "kein",
while "I don't eat cheese" uses "keinen" ?
Aren't they both Accusative Case thus keinen?
Really confused here
Check "copula" on Wikipedia. https://en.wikipedia.org/wiki/Copula_(linguistics)
The "copula" always goes in nominative case, in German.
In all the other cases, the complements go in either accusative (for direct/transitive verbs) or dative (for indirect/intransitive verbs) cases.
Genitive does not usually complement a verb (might be wrong here, but I can't think or recall any such instance) .
Es ist kein Käse. It is not a cheese. In this sentence, Käse is in the nominative case. The subject of the sentence is "es" , but there is equality between "es" and "Käse" , so I guess Käse can be treated like the subject.
But in Ich esse keinen Käse, Käse is in the accusative case.
"Ich esse keinen Käse" is correct.
If you want to say "He does not eat cheese" that would be "Er isst keinen Käse", so isst with double s and keinen with en at the end.
You sentence "Er ist kein Käse" made me smile a bit, because that means "He is not a cheese" like in "He is a human being, not a cheese."
Edit: Seems like I read too quickly, ES ist kein Käse means of course IT is no cheese. Sorry, my mistake.