Learn Icelandic: Hvert barn þrífur eitt klósett hvern dag. - Each child cleans one toilet every day.

Both are forms of the word hver (each/every), but they change to match the noun they describe. Barn (child) is a neuter noun acting as the subject (nominative case), so it takes the neuter nominative form hvert. Dagur (day) is a masculine noun. Here, it is in the accusative case because it is part of a time expression, so it takes the masculine accusative form hvern.

Why is the time expression hvern dag in the accusative case?

In Icelandic, phrases that express how often or how long something happens (like 'every day', 'all night', or 'for a year') are usually put into the accusative case.

Why use eitt klósett instead of just klósett?

Icelandic does not have words for 'a' or 'an', so just saying þrífur klósett would usually mean 'cleans a toilet' or 'cleans toilets'. By adding eitt (the neuter accusative form of the number one), the sentence emphasizes that the child cleans exactly one toilet.

What is the difference between þrífa and hreinsa?

Þrífa is usually the go-to verb for household chores that involve scrubbing, washing, or wiping surfaces, making it the perfect word for cleaning a bathroom. Hreinsa is more about clearing things away or purifying, like clearing snow off a car or cleaning a wound.