Irrealis mood is used to indicate that a certain situation or action is not known to have happened as the speaker is talking.  It’s a way of expressing an event or thing that is non-actual, or non-factual at the time that the speaker is telling it.

For example, irrealis is used to express things that haven’t happened, nearly happened, won’t happen, might happen, might not happen, or we wish they’d happen.

English doesn’t have a single way of expressing this, but many Australian Indigenous languages do. Some examples in English of sentences that may use an irrealis form in an Indigenous language:

    • If I had been there then I would have….
    • I didn’t see the dog
    • You should have gone
    • He probably went home
    • I wish it would rain
    • She might get sick

Note that all these sentences refer to situations that have not happened, they’re not currently ‘real’, consequently ‘irrealis’