Learn Croatian: Hoćeš li mi pomagati sutra? - Will you be helping me tomorrow?

This is about verbal aspect, which is the focus of your current lesson! pomagati is an imperfective verb, meaning it focuses on the ongoing process of helping. It translates to "will you be helping me" (maybe for a few hours, or as an ongoing task). If you used the perfective verb pomoći, it would mean "Will you help me?" as a single, completed action.

Why is the word for "me" mi here, rather than me?

In Croatian, the verbs for "to help" (pomagati and pomoći) always require the dative case, because you are giving help to someone. mi is the short dative form for "me". The word me is the accusative form, which is used for direct objects but is incorrect with this specific verb.

Why does the question start with Hoćeš li instead of the usual future tense word ćeš?

To form a yes/no question using li, you must use the long form of the helper verb htjeti (to want/will). The long form for "you" is hoćeš. The short form ćeš is a clitic (a "weak" word without its own accent), and Croatian grammar rules state that a clitic can never be the very first word in a sentence.

Could we change the word order to Hoćeš mi li pomagati sutra?