Questions & Answers about Szef każe mi wcześnie wstać.
Why do we use mi here instead of mnie?
The verb kazać (to order or tell someone to do something) requires the Dative case for the person receiving the command. mi is the short, unstressed Dative form of the pronoun for I. We use it here because it is tucked into the middle of the sentence. You would only use the long form mnie if you wanted to heavily emphasize that the boss tells ME, not someone else.
Doesn't powiedzieć also mean to tell? Why use każe?
They mean to tell in different ways. You use powiedzieć when you are passing on information, like telling a fact. You use kazać when you are telling someone to do an action, like giving a command or instruction. Because the boss is giving an order to get up, we need a form of kazać.
What is the infinitive of każe? The spelling seems irregular.
The infinitive is kazać. It is an irregular verb where the z changes to ż in the present tense. For example, it conjugates as ja każę, ty każesz, and on or ona każe.
Why is the word wstać in the infinitive form here?
When a verb like kazać commands an action, the action itself is expressed as an infinitive. This is just like English, where we say tells me TO GET up rather than conjugating the second verb.