allir

In a sentence

• Allir eru glaðir í dag.

  Everyone is happy today.

  In this sentence, 'allir' is used as a pronoun meaning 'everyone', referring to all the people being discussed.

• Allir nemendur skiluðu verkefninu á réttum tíma.

  All the students submitted the assignment on time.

  Here, 'allir' is used as a descriptor adjective for 'nemendur' (students), emphasizing that every single student completed their task.

• Við skulum þakka fyrir alla hjálpina sem við fengum.

  We should be grateful for all the help we received.

  In this case, 'alla' is the accusative plural form of 'allur', agreeing with 'hjálpina' (the help) to denote inclusion of all help received.