Learn Italian: Alzati immediatamente, il treno è arrivato! - Get up immediately, the train has arrived!

Alzati is the imperative (command) form of the reflexive verb alzarsi (to get up). In Italian, when you give an informal affirmative command, pronouns like the reflexive ti must be attached directly to the end of the verb.

Would the command change if I was telling a group of people to get up?

Yes! If you were talking to a group using the plural you (voi), the verb becomes alzate and the reflexive pronoun is vi. So, the command would be alzatevi.

Why do we use è instead of ha in è arrivato?

The verb arrivare (to arrive) is a verb of motion. In the past tense, verbs of motion use essere (to be) as their helping verb instead of avere (to have). Therefore, we say il treno è arrivato instead of using ha.

Does the ending of arrivato change depending on what arrived?