Learn Icelandic: Skammturinn er ein pilla á dag.

When talking about how often something happens, Icelandic uses specific prepositions for different time periods. For "per day" or "a day", you always use á dag. If you were to say í dag, it would change the meaning to "today"! Remember that other time words take different prepositions, like í viku for "a week".

Why is the word for "one" spelled ein here?

The number one changes its form to match the gender of the noun it counts. Because pilla (pill) is a feminine word, you must use the feminine form ein. If you were counting a masculine word, like skammtur (dose), you would use einn.

How does the word skammturinn break down?

It is made up of the masculine noun skammtur (a dose or portion) and the attached definite article -inn (the). In Icelandic, "the" is usually hooked onto the end of the word rather than coming before it, making it literally "dose-the".