Hún er mjög dugleg í vinnunni og klárar oft verkefnin sín fyrr en ég.

Because dugleg has to agree with hún (she).

The adjective duglegur means something like hardworking / diligent. Its form changes depending on gender, number, and case:

• duglegur = masculine singular
• dugleg = feminine singular
• duglegt = neuter singular

Since hún is feminine singular, the correct form is dugleg:

• Hún er mjög dugleg. = She is very hardworking.

í vinnunni literally means in the work or more naturally at work / in the workplace.

Here is the breakdown:

• vinna = work
• vinnunni = the work in the dative singular

The ending -unni includes the definite article, so Icelandic often says something closer to in the work where English would simply say at work.

So:

• í vinnu = at work / in work
• í vinnunni = at the workplace / at work

In this sentence, í vinnunni is the natural idiomatic expression.

Because the preposition í often takes the dative when it describes location.

A very important Icelandic rule is:

• í + dative = in / at somewhere, when there is no movement
• í + accusative = into somewhere, when there is movement toward it

Here, the sentence describes where she is hardworking: at work, not movement into work. So Icelandic uses the dative:

• í vinnunni = at work

Compare:

• Hún er í húsinu. = She is in the house. (location, dative)
• Hún fer í húsið. = She goes into the house. (movement, accusative)

Mjög means very.

It is an adverb that strengthens the adjective dugleg:

• dugleg = hardworking
• mjög dugleg = very hardworking

So:

• Hún er dugleg. = She is hardworking.
• Hún er mjög dugleg. = She is very hardworking.

Klárar is the present tense form of að klára, meaning to finish.

It agrees with a third-person singular subject:

• ég klára = I finish
• þú klárar = you finish
• hann/hún/það klárar = he/she/it finishes

Since the subject is hún (she), the sentence uses:

• hún klárar = she finishes

So:

• Hún ... klárar oft verkefnin sín ...
• She often finishes her tasks ...

Because oft (often) is an adverb, and Icelandic commonly places adverbs like this before the object.

So the structure is:

• klárar oft verkefnin sín
• literally: finishes often her tasks
• natural English: often finishes her tasks

This kind of word order is very normal in Icelandic. Adverbs such as oft, alltaf, aldrei often come before the main object.

Compare:

• Hann les oft bókina. = He often reads the book.
• Ég sé hana stundum. = I sometimes see her.

Because sín is a reflexive possessive, used when the possessor is the same as the subject of the clause.

In this sentence, the subject is hún (she), and the tasks belong to that same person. So Icelandic uses sín:

• Hún klárar verkefnin sín.
• She finishes her own tasks.

If you said verkefnin hennar, that would usually mean her tasks belonging to some other female person, not necessarily the subject.

So the contrast is:

• Hún klárar verkefnin sín. = She finishes her own tasks.
• Hún klárar verkefnin hennar. = She finishes another woman’s tasks.

This is one of the most important differences from English, because English uses her for both meanings.

Because sinn changes form to agree with the noun it describes, not with the subject.

The noun here is verkefnin (the tasks), which is neuter plural definite. The matching possessive form is sín.

Very roughly, the reflexive possessive has forms like:

• sinn = masculine singular
• sína = feminine singular / some other forms depending on case
• sitt = neuter singular
• sín = plural in some forms, including the one used here

Since verkefnin is plural, sín is correct:

• verkefnin sín = her own tasks

Verkefnin means the tasks / the assignments, while verkefni would be tasks / assignments more generally.

In Icelandic, using the definite form can make the phrase sound more like specific tasks that she has. English may or may not use the in the same situation.

So:

• verkefni = tasks, assignments
• verkefnin = the tasks, the assignments

Then:

• verkefnin sín = her own tasks
• literally: the tasks of hers (her own)

This is very natural Icelandic.

Fyrr en ég means earlier than I do or simply before me / sooner than I do, depending on how naturally you translate it.

• fyrr = earlier / sooner
• en = than
• ég = I

So the idea is:

• She often finishes her tasks earlier than I do.

In Icelandic, the verb after ég is often left unstated because it is understood from the earlier part of the sentence:

• fyrr en ég [klára mín verkefni]

English does the same:

• earlier than I do rather than repeating
• earlier than I finish my tasks

This is a very common learner question.

In careful Icelandic, after a comparison with en (than), you often see the nominative form:

• fyrr en ég

This is similar to formal English than I or than I do, rather than than me.

The idea is that there is an implied verb after ég:

• fyrr en ég [geri / klára]

So ég is acting like the subject of an understood clause, which is why nominative makes sense.

In everyday language, comparison structures can vary, but fyrr en ég is completely standard and a good model to learn.

Here it means earlier / sooner, not exactly faster.

So the sentence is not mainly about speed in the sense of working quickly moment by moment. It is about the result happening earlier:

• she finishes earlier than I do

Of course, that may imply she works faster or more efficiently, but grammatically fyrr is about time:

• fyrr = earlier, sooner

If you wanted to talk more directly about speed, Icelandic would use other words and structures.

Yes: the sentence shows very normal Icelandic main-clause word order.

Structure:

• Hún = subject
• er = verb
• mjög dugleg í vinnunni = complement
• og = and
• klárar = verb
• oft = adverb
• verkefnin sín = object
• fyrr en ég = comparison

A key thing for learners is that Icelandic often puts adverbs like oft before the object:

• klárar oft verkefnin sín

Also, Icelandic does not need to repeat everything in the comparison:

• fyrr en ég instead of spelling out
• fyrr en ég klára verkefnin mín

So the sentence is compact, natural, and very typical Icelandic.

Not very naturally.

A rough word-for-word version would be:

• She is very hardworking at the-workplace and finishes often the-tasks own earlier than I.

That sounds strange in English, but it helps show the Icelandic structure.

A natural English translation would be:

• She is very hardworking at work and often finishes her tasks earlier than I do.

This is a good reminder that Icelandic and English often express the same idea with different article use, word order, and possessive patterns.