Passive Voice

In English, we use the verb to be plus the past participle to form the passive voice. In German, things are mighty similar, but the auxiliary verb is werden.

Unsere Fehler wurden von ihm korrigiert.
Our mistakes were corrected by him.

The auxiliary verb gives us information about the time of the action, and the participle tells us about what happened.

So this means that we just have to know the conjugation of werden in order to make any passive sentence in German.

Das Haus wird gebaut.
The house is being built.

If we ever have cause to use the future passive, we end up with two forms of werden in the same sentence, though it's none the worse for understanding.

Die Autos werden gekauft werden.
The cars will be bought.

It turns out that, stylistically, German uses the passive significantly less than English does.

Instead of: Hier wird Deutsch gesprochen.
German is spoken here.
try:PHier spricht man Deutsch.
One speaks German here. (German is spoken here.)

There's one other structure that sort of overlaps with the passive voice semantically.

If we use lassen as a helping verb (plus infinitive), it has the sense of "having something done" without being involved. Kind of like a passive related to yourself, as you're not an active participant in the events.

Ich lasse mein Auto reparieren.
I'm having my car repaired.

Er lässt seine Fenster waschen.
He's having his windows washed.