Learn Finnish: Miksi minun täytyy lähteä aikaisin?

The verb täytyy (must / have to) is a special type of verb in Finnish. The person who has to do something must be written in the genitive case (the 'owning' form). That is why we use minun (my) instead of minä (I).

Does the verb täytyy change endings depending on who is leaving?

No! Täytyy is a 'frozen' verb, meaning it does not take personal endings like normal verbs do. It always stays as täytyy, whether it is you, me, or someone else who must do something.

Why is lähteä used in its basic dictionary form?

When you use täytyy, the action verb that follows it always stays in its basic infinitive form (the dictionary form). This is similar to English, where we say 'must leave' instead of 'must leaves'.

How does the question word miksi affect the sentence structure?

Question words like miksi (why) simply go at the very beginning of the sentence. Unlike yes/no questions which attach -ko or -kö to a verb and move it to the front, miksi questions keep the standard statement word order right after the question word.