Learn Hardcore Icelandic: Hann er farinn heim.

Breakdown of Hann er farinn heim.

Why does Icelandic say er farinn here instead of just using a simple past form?

Because Hann er farinn heim does not work exactly like a plain simple past such as Hann fór heim.

Hann fór heim = He went home.
This simply reports the action.
Hann er farinn heim = He has gone home / He is gone home.
This stresses the resulting state: he has left, and he is now away.

So er farinn is often used when the important idea is that the person is already gone.

What exactly is farinn?

Farinn is the past participle of fara (to go).

In this sentence, it is used with er (from vera, to be) to form a meaning like has gone or is gone.

It also behaves a lot like an adjective, which is why it changes form depending on who is being talked about.

For example:

So farinn is not a fixed form; it agrees with the subject.

Why is it farinn and not some other form of the participle?