Breakdown of Við hvílum hundana um daginn.
hundurinn
the dog
við
we
dagurinn
the day (m)
um
over / during (a period of time)
Questions & Answers about Við hvílum hundana um daginn.
Doesn't um daginn usually mean 'the other day'?
It does when used with the past tense! However, when describing routines or present actions, the preposition um followed by the accusative case indicates a broad temporal period. In this sentence, um daginn literally means 'during the day' or 'in the daytime'.
Why is hundana in the accusative case?
The verb hvíla takes the accusative case when it has a direct object. Because we are actively giving the dogs a rest, hundana acts as the direct object receiving the action.
What if we were just resting ourselves? Would we still use hvíla?
If you are resting yourselves, you would use the middle voice verb hvílast without an object, as in við hvílumst (we rest). You only use the active voice hvíla when you are resting someone or something else, like the dogs.
Why does Icelandic use the definite article in um daginn?
Icelandic almost always requires the definite form of the noun for these broad time-of-day phrases. Just as you say um daginn for 'during the day', you would say um nóttina for 'during the night' and um morguninn for 'during the morning'.