Breakdown of Ich erzähle einem Opa und einer Oma eine Geschichte.
ich
I
ein
a, an (eine)
und
and
erzählen
to tell
Questions & Answers about Ich erzähle einem Opa und einer Oma eine Geschichte.
Why does the sentence use einem for grandpa but einer for grandma?
They are both in the dative case because they are the people receiving the story. The dative case changes words based on gender. Because Opa is a masculine noun, ein changes to einem. Because Oma is a feminine noun, eine changes to einer.
Why isn't eine Geschichte also in the dative case?
Die Geschichte (the story) is the direct object here, which means it is the actual thing being told. Direct objects take the accusative case, not the dative. Since Geschichte is a feminine noun, its accusative article is just eine, which looks exactly like its basic dictionary form.
Why do the grandpa and grandma come before the story in the sentence?
In German word order, when a sentence has both a dative object (the receiver, like the grandparents) and an accusative object (the thing, like the story), the dative object almost always comes first. This is why einem Opa und einer Oma is placed before eine Geschichte.
How do I know that erzählen needs the dative case?
Verbs involving giving, showing, or telling usually take a dative object for the person receiving the action. With erzählen (to tell), the person you are telling the story to is the indirect receiver of your action, so they must be in the dative case.