"A duck is not a dog."
Translation:Kaczka nie jest psem.
So why does nie come before jest if the sentence is "Kaczka nie jest psem." ?
This is how I see it, but I am not sure this is the best (correct?) explanation... Let us skip "kaczka" to make it simpler. Consider the following four sentences.
"It is barking. It is a dog." = "Szczeka. To pies"/"Szczeka. Jest psem"
"This is a dog" = "To jest pies" (e.g. when pointing at a dog)
"This is a not dog" = "To nie jest pies" (e.g. when pointing at a cat)
"It is not barking. It is not a dog." = "Nie szczeka. To nie pies"/"Nie szczeka. Nie jest psem"
So we have the following grammaticaly correct sentences "To pies. To jest pies. To nie jest pies. To nie pies." (they are not equivalent in meaning (and the precise meaning could depend on the context/intonation/etc.) and the role of the word "to" varies in those sentences). Basically "nie" comes before the verb ("jest") and the verb comes after "to". When using all three "nie" is after "to", but before "jest" (unless you want to say "Nie, to jest pies" = "No, this is a dog" ;P). When you skip the verb ("jest"), the order does not change.
Is this helpful? Does somebody have more insight?
PS: You could use also "Kaczka to nie jest pies", but again the meaning would be a little bit different (more emphasis) from "Kaczka to nie pies"/"Kaczka nie jest psem".
I thought negative verbs take the genitive case wouldn't that make it (the dog) psa?
Negation changes accusative to genitive , but instrumental or nominative , (or locative, or dative) do not change
I'd have to see your whole sentence.
Generally, the accepted versions are "Kaczka nie jest psem" and "Kaczka to nie pies". "Kaczka to nie jest pies" is acceptable, but uncommon.
You can say that, but that's not really a sentence...
But we do use such a construction sometimes, most notably "Robota nie zając, nie ucieknie" (Work is not a hare, it won't run away - with a colloquial word for 'work').