Learn Croatian: Radnici kreću u zoru. - The workers set off at dawn.

This is due to a sound change called sibilarization. In Croatian, when a masculine word ends in -k, -g, or -h, that consonant changes to -c, -z, or -s before the plural ending -i. So, the k in radnik becomes a c in radnici.

The verb here is kreću, but the dictionary form is kretati. Where does the ć come from?

Many Croatian verbs ending in -ati undergo a consonant change in the present tense. For kretati, the t changes to ć, creating the present tense stem kreć-. Adding the third-person plural ending -u gives us kreću.

Why is u zoru in the accusative case here instead of the locative?

While the preposition u takes the locative case to describe a static location, it takes the accusative case for certain time expressions. Just like you use the accusative for days of the week, such as u srijedu (on Wednesday), you use it for specific times of day like u zoru (at dawn).

Does kretati always mean to set off?