Why do certain prepositions require dative & certain require accusative?

[Macnerd]

I've tried to find the answer on the internet but all I've found is lists of dative prepositions & lists of accusative prepositions & lists of prepositions that use either dative or accusative. I can never get straight which case is for direct objects & which case is for indirect objects.

So, why do certain prepositions require dative & certain require accusative?

[h34]

As a rule of thumb, you can say that the accusative case is used to mark the direct object, while the dative case marks the indirect object:

Sie fragt ihn.
sie "she", nominative
fragt "asks, is asking"
ihn "him", accusative (direct object)

Sie gibt ihm den Schlüssel.
gibt "gives, is giving""
ihm "(to) him", dative (indirect object)
den Schlüssel "the key", accusative (direct object)

This rule doesn't apply if certain prepositions are used:

Sie spricht mit ihm.
spricht "talks"
mit ihm "to him (lit. with him)", dative (!)


With locations, the accusative case tends to be used to describe a movement towards something, towards somewhere, into something etc.. The dative describes a "static" location or a movement out of somewhere or away from somewhere:

Sie fährt in die Stadt.
fährt "drives, is driving"
in die Stadt "(in)to the town", accusative

Sie wohnt in der Stadt.
wohnt "lives, dwells"
in der Stadt "in the town", dative

Sie kommt aus der Stadt.
kommt "comes, is coming"
aus der Stadt "out of the town", dative

I've just come across this website. Perhaps it's useful:
https://coerll.utexas.edu/gg/gr/cas_01.html

[kevin]

So, why do certain prepositions require dative & certain require accusative?

I hope I don't confuse you instead of helping, but there are also prepositions requiring the genitive.

I guess this is just how prepositions work in languages with cases.