Learn Italian: Voi siete fratelli?

In Italian, there is a difference between talking to one person and talking to multiple people. Because you are asking if they are brothers, you are talking to more than one person. Voi is the plural 'you' (like 'you all' or 'y'all'), and it pairs with the verb form siete (are).

Do I have to include the word voi?

No, you could simply ask, 'Siete fratelli?' In Italian, you can usually drop the subject pronoun because the verb itself tells us who is doing the action. Siete only ever means 'you all are', so the voi is already understood.

Why is the word order exactly the same as the statement 'You are brothers'?

To ask a yes or no question in Italian, you do not need to swap words around like in English. You just use the exact same word order as a regular statement and make your voice go up at the end (or use a question mark in writing).

Could fratelli also mean 'siblings'?

Yes! In Italian, if a group has a mix of males and females, you use the masculine plural word. So, fratelli translates to 'brothers', but it is also the word you use to mean 'siblings' (for example, a brother and a sister). If you were talking to strictly females, you would ask, 'Voi siete sorelle?'