What is the difference between 'Znamy tamten mężczyzna" and "Znamy tamtego mężczyznę?"I know it's a different case but beyond that?
Mężczyzna is nominative, and mężczyznę is accusative. In this sentence, the man is on the receiving end of the verb (znamy), so it's in the accusative. If the sentence were the other way around (the man knows us), it would be the nominative version.
The main difference is that 'Znamy tamten mężczyzna' is incorrect.
Does the accusative animate only work for masculine and nueter nouns and not for feminine nouns or am I unaware of the accusative animate for female nouns?
Only masculine nouns decline differently when they're personal, animate, or inanimate.
why : in this case : mężczyznę
and : sluchacie tego mezczyzny ? ( sorry I cannot type the accents, the first time I copied it )
Cases. Different verbs (and prepositions) need different cases. "znać" (to know) takes Accusative, which is "mężczyznę". "słuchać" (to listen to) takes Genitive, which is "mężczyzny".
Isn't accusative form for animate masculine nouns identical to genitive?
It usually is, but "mężczyzna" is one of those weird masculine nouns that look like and behave like feminine ones anyway.
How do we know when and what case to use in conversation?
The same ones you use in writing.