If we were to go into detail, would it be true that
"Meine Frau isst keinen Käse" means "My wife eats no cheese" and,
"Meine Frau isst Käse nicht" translates as "My wife does not eat cheese" or "My wife is not eating cheese" depending on the context?
Just trying to work out the difference between using "keinen" and "nicht" in the sentence.
I still don't manage the cases (kein / keinen) but in general, "nicht" is just negation and "kein" stands for something missing or the exclusion of something. "There is no food in the fridge" or "i eat fish but no meat", use kein. "I don't eat meat", use "nicht". With "nicht", if you don't precise, it can either be a general or precise situation.
So first there is "kein" and "keine." Keine is used with feminine words, while Kein is masculine. So, for example, "Keine Katze mag Nudeln" versus "Kein Hund mag Nudeln." These are in the Nominative case, where the thing you are talking about (Katze/Hund) is the Subject, doing the action. (Determiners are m:ein/kein/der, f:eine/keine/die, n:ein/kein/das, pl:keine/die). There are two other main cases: Akkusitive and Dativ. In a nutshell, Akkusitive is when it recieves an action, in which case the endings are : (m:einen/keinen/den, f: eine/keine/die, n:ein/kein/das, pl:keine/die). Some examples of this case are: "Ich hab einen Hund" or "Ich hab eine Katze". That is where this example comes in because we need to use the Akkusative case. The last one is Dativ, where you use prepositions. The words are: (m:einem/keinem/dem, f:einer/keiner/der, n:einem/keinem/dem, pl:keinen/den). You use it after prepositions such as "in," "unter," "auf," "neben," etc. Some examples are: "Ich bin unter dem (m) Dom," or "Ich bin neben der Katze". And usually the determiners are interchangeable in the same gender (ex. dem Dom vs. einem Dom vs. keinem Dom, they all work). It seems complicated at first, but after you understand it it becomes generally easy.
Which of kein/keine/keinen you use is exactly the same as which of ein/eine/einen you would use. If the question is when to use kein vs. nicht, kein should be used whenever an indefinite article (ein/eine/einen) is, and if there is no article at all (so no das/die/der or ein) then you can either use kein (which negates the noun) or nicht (which negates either the verb or the whole sentence) depending on what you want to say.
I'm not a native speaker by any means, but that is my current understanding of it, and I haven't lost a heart from it so far.
Die Frau, eine Frau, keine Frau; das Haus, ein Haus, kein Haus; der Mann, ein Mann, kein Mann. Only "der" changes in the accusative case to "den": Ich sehe den Käse. Ich esse einen Apfel. Ich trinke keinen Alkohol. But: Ich trinke keine Milch (die Milch). Ich trinke kein Bier (das Bier).
Der Käse - kein Käse - keinen Käse (accusative case): Ich esse keinen Käse. Das Brot (bread) - kein Brot (nominative and accusative): ich esse kein Brot.
Die Pizza - keine Pizza: Ich esse keine Pizza (accusative). Die Kartoffel (singular), die Kartoffeln (plural): Ich esse keine Kartoffeln. The pronoun "kein" turns only before masculine nouns into keinen. Ein, mein, dein und sein too.
'Kein' is 'nicht ein (masculine or neuter)' = not a(n) or not any: Das ist kein Wolf (der Wolf). (That is not a wolf). Dies ist kein Zebra (das Zebra). 'Keine' is in the singular 'nicht eine' = also 'not a(n)' or 'not any' (for a feminine noun): Das ist keine Gans (die Gans = the goose). In the plural 'keine' means 'less than': Das sind keine hundert Gramm. (Those are less than one hundred grams)
Because Käse is a masculine noun and it's the direct object of the verb essen, so it's in the accusative case.
So you need the masculine accusative form of kein, which is keinen.
kein would be masculine nominative or neuter nominative; keine would be feminine or plural and, in either case, nominative or accusative.
What I'm having a little trouble wrapping my head around is that, in this case, we are negating the noun and not the verb. To me, we should negate the verb because she's does not eat something. Which leads me to my question, would there be a difference in meaning if we negated the verb instead?
"Meine Frau isst keinen Käse" My wife does not eat cheese. (She doesn't like cheese or she's lactose intolerant.)
"Meine Frau isst nicht Käse." My wife is not eating cheese. (She didn't choose cheese when she was getting hors d'oeuvres. She is not eating cheese at the moment.).
Am I wrong here? I'm trying to understand the difference between negating the noun or the verb and how that changes the meaning.