Hún skrifar allt á verkefnalistann sinn og klárar tvö atriði fyrir hádegi.

The basic noun is verkefnalisti, meaning task list or to-do list.

In the sentence, it appears as verkefnalistann because it is:

• singular
• definite: the task list
• accusative

The -nn at the end is the suffixed definite article, so verkefnalistann means the task list.

It is also in the accusative because it follows á in a context of putting/writing something onto a surface or destination:

• á verkefnalistann = onto/on the task list

A useful contrast is:

• á verkefnalistann = onto the list / on the list as something is being added
• á verkefnalistanum = on the list, in a more static sense

Because Icelandic uses a reflexive possessive when the possessor is the same as the subject of the clause.

Here, the subject is Hún (she), and the list belongs to that same person, so Icelandic says:

• verkefnalistann sinn = her own task list

If you used hennar, it would normally sound non-reflexive, meaning the list belongs to some other female person, not the subject herself.

Also, sinn changes form to agree with the thing possessed. Since verkefnalistann is masculine singular accusative, the correct form is sinn.

Here allt functions like a pronoun, meaning everything.

It comes from allur (all), and the neuter singular form allt is often used by itself to mean:

• allt = everything

In this sentence, it is the direct object of skrifar:

• Hún skrifar allt = She writes everything

Grammatically, it is accusative here, but in the neuter singular the nominative and accusative forms look the same.

Because Icelandic commonly says skrifa eitthvað á eitthvað for write something on/onto something.

So:

• skrifa allt á verkefnalistann = write everything on/onto the task list

This is just the normal Icelandic pattern with skrifa in this kind of context.

There is also a case point here: á can take either accusative or dative, depending on meaning. With accusative, it often suggests movement, direction, or result. Since the items are being put onto the list, accusative makes sense.

Because Icelandic numbers from one to four change according to gender.

The word atriði is neuter, so the form of two must also be neuter:

• masculine: tveir
• feminine: tvær
• neuter: tvö

So:

• tvö atriði = two items

That is the correct agreement.

In this sentence, atriði means something like:

• item
• point
• task
• thing on a list

So tvö atriði is naturally understood as two items or two tasks.

This is a flexible word in Icelandic. In other contexts, atriði can also mean:

• a point in an argument
• a detail
• a matter/issue
• even a scene or numbered item, depending on context

Here, because the sentence is about a task list, items is the most natural interpretation.

Klárar is the 3rd person singular present tense of klára, meaning:

• to finish
• to complete

So:

• hún klárar tvö atriði = she finishes/completes two items

This is a very common everyday verb in modern Icelandic.

Fyrir hádegi means before noon.

The preposition fyrir is often used in time expressions to mean before:

• fyrir hádegi = before noon
• fyrir kvöld = before evening

The noun hádegi means noon / midday. After fyrir, accusative is used here, but hádegi has the same form in nominative and accusative singular, so you do not see a visible change.

Because the second verb has the same subject as the first one, and Icelandic often leaves the repeated subject out in coordinated clauses, just like English often does.

So:

• Hún skrifar allt ... og klárar tvö atriði ...

means:

• She writes everything ... and finishes two items ...

You could repeat hún, but it is usually unnecessary here.

Yes. Both are present tense, 3rd person singular forms:

• skrifar = writes
• klárar = finishes/completes

In a sentence like this, the present tense can describe:

• a habitual action
• a routine
• something happening in a narrative or summary style

So the Icelandic present tense works quite similarly to the English simple present in this kind of sentence.