Learn Croatian: Umjesto da rade zajedno, oni se natječu jedan s drugim. - Instead of working together, they compete with each other.

In Croatian reciprocal phrases using jedan drugi (each other), any preposition must be inserted directly between the two words, not placed at the beginning of the phrase. You will always see jedan s drugim (one with another) rather than s jedan drugim.

Why are the words jedan and drugim in two different cases?

In this construction, the first word (jedan) always stays in the nominative case, acting as a sort of subject. The second word (drugi) must change its case to match whatever preposition comes right before it. Because the preposition s requires the instrumental case, drugi becomes drugim.

English uses 'instead of working'. Why does Croatian use umjesto da rade?

Croatian does not use gerunds (verb forms ending in -ing) after prepositions. When you want to express 'instead of doing something', you must use the conjunction umjesto da followed by a fully conjugated verb. Here, that is the present tense rade (they work).

The verb natječu se already has the reflexive se. Isn't jedan s drugim redundant?