Learn Croatian: Konobar je gospodinu donio kavu. - The waiter brought the gentleman a coffee.

The waiter is bringing the coffee to the gentleman. In Croatian, the person receiving something takes the dative case. For most masculine nouns like gospodin, you make the dative by adding -u to the end, giving us gospodinu.

Why is it kavu and not kava?

The coffee is the direct object, which is the thing being brought. So the feminine noun kava changes to the accusative case, which ends in -u, making it kavu. Notice how both gospodinu and kavu end in -u here, but they are in different cases (dative and accusative) because one is a masculine word and the other is feminine.

Why are the verb parts je and donio separated by the word gospodinu?

The past tense is made of two parts: the helper word je and the main action word donio. In Croatian, short helper words like je usually have to sit in the second position in the sentence. The rest of the sentence is flexible, so it is perfectly normal for a word like gospodinu to slip between the two verb parts.

Could I change the word order and say Konobar je donio kavu gospodinu?