This is the 494th most frequent Icelandic word.
ætti
"Ætti" means "should" or "ought to" in English.
In this sentence, 'ætti' functions as a modal verb meaning 'should', indicating an obligation or suggestion.
Ég ætti að læra meira í kvöld.
I should study more tonight.
Here, 'ætti' is used in the second person singular, conveying advice or recommendation.
Þú ættir að hringja í hana.
You ought to call her.
In this context, 'ætti' expresses a suggestion combined with a conditional situation.