Learn Croatian: Danas se nisam rano probudio. - I did not wake up early today.

Instead of using the normal, positive helper word sam (am), we use the negative version nisam (am not). To make the negative past tense, you just combine this negative helper (nisam) with the past action word (probudio).

Why does se come before nisam here?

In a positive sentence, the helper sam is a weak word (a clitic) that takes the strict second position, and se comes after it. However, the negative word nisam is a strong, full word, not a clitic! Because of this, the weak word se grabs the second position right after the first word (Danas), and nisam follows it.

How would a woman say this exact sentence?

A woman would say: Danas se nisam rano probudila. In the Croatian past tense, the action word changes based on the speaker's gender. Because it ends in -o (probudio), we know a man is speaking here. A female speaker uses the -a ending instead.

Why is the word se used for waking up?

The Croatian verb for waking up is probuditi se. The se means 'oneself', so you are literally saying 'I did not wake myself up early today'. Many verbs dealing with personal daily routines require se like this.