Hún ætlar að stytta faldinn á pilsinu í kvöld.

Ætlar að + infinitive is a very common way to express intention in Icelandic.

So Hún ætlar að stytta... means she intends / is going to shorten something.

A few useful points:

• ætla is the verb
• að introduces the infinitive
• stytta is the infinitive that follows

It often corresponds to English be going to, but the core idea is usually intention rather than a purely neutral future.

In Icelandic, að is the normal infinitive marker, much like English to.

So:

• að stytta = to shorten

After ætla, Icelandic normally uses að + infinitive:

• Hún ætlar að fara = She is going to go
• Hún ætlar að stytta = She intends to shorten

So the að is not optional here in normal usage.

Because it depends on ætlar að.

The finite verb in the sentence is ætlar. That is the verb that is conjugated for person and number. The next verb stays in the infinitive:

• Hún ætlar = she intends
• að stytta = to shorten

This is similar to English:

• She intends to shorten...

You do not conjugate both verbs.

Because faldinn is the accusative singular definite form, while faldur is the basic dictionary form, the nominative singular indefinite.

Here, faldinn is the direct object of stytta:

• stytta hvað? = shorten what?
• faldinn = the hem

So Icelandic marks that role with the accusative.

A helpful breakdown:

• faldur = a hem
• faldinn = the hem

And in this sentence, the direct object needs that accusative definite form.

Icelandic usually puts the definite article onto the end of the noun instead of using a separate word like English the.

So:

• faldur = hem
• faldinn = the hem

and

• pils = skirt
• pilsinu = the skirt

The exact ending changes depending on:

• gender
• number
• case

So the article is not one fixed form. It merges with the noun and changes shape.

Here á pilsinu means something like on the skirt.

In the phrase faldinn á pilsinu, Icelandic expresses the relationship literally as the hem on the skirt, where English would more naturally say the hem of the skirt.

So:

• faldinn á pilsinu = the hem on the skirt / the skirt’s hem

This is a normal Icelandic way to connect the two nouns.

Because the preposition á can govern different cases, and here it is used in a location / position sense, which takes the dative.

Compare the basic idea:

• á
  • dative = on, at, resting on
• á
  • accusative = onto, into contact with, movement toward a surface

In faldinn á pilsinu, nothing is moving onto the skirt. It is simply the hem on the skirt, so the dative is used:

• pilsinu

Also, pils is a neuter noun, and pilsinu is its dative singular definite form.

Yes, in effect.

English would usually say:

• the hem of the skirt
• the skirt’s hem

But Icelandic often uses a prepositional phrase here:

• faldinn á pilsinu

So you should not translate word-for-word too rigidly. The Icelandic structure is natural even though English prefers a possessive or of-phrase.

Hún is nominative singular, because it is the subject of the sentence.

It is the form meaning she.

A very simple case overview here:

• Hún = subject, nominative
• faldinn = direct object, accusative
• pilsinu = object of the preposition á, dative

So this sentence is a good example of Icelandic case marking doing a lot of grammatical work.

This is a normal, neutral Icelandic word order:

• subject: Hún
• finite verb: ætlar
• infinitive phrase: að stytta
• object: faldinn
• prepositional phrase modifying that object: á pilsinu
• time expression: í kvöld

So the sentence flows very naturally as:

She intends to shorten the hem on the skirt tonight.

That said, Icelandic word order is somewhat flexible, especially with adverbials like í kvöld. For example, you may also see:

• Hún ætlar í kvöld að stytta faldinn á pilsinu

But the original version is the most straightforward neutral order.

Í kvöld is a fixed time expression meaning tonight / this evening.

Here:

• í = in
• kvöld = evening

But you should learn í kvöld as a set phrase, not as a fully literal word-for-word expression.

It functions adverbially, telling you when the action will happen.

Other similar time expressions are:

• í dag = today
• í morgun = this morning
• í nótt = tonight / during the night

• faldur is masculine
• pils is neuter

That matters because gender affects:

• case endings
• article endings
• adjective agreement

In this sentence you can see that in the forms:

• faldinn = masculine accusative singular definite
• pilsinu = neuter dative singular definite

Learning the gender with each noun is very important in Icelandic, because the endings depend on it.

Normally, no. Icelandic usually keeps the subject pronoun.

So:

• Hún ætlar að stytta... = normal

Unlike some languages, Icelandic is generally not a pro-drop language. Even though the verb form gives some information, the pronoun is still usually expressed.

No. Stytta is a general verb meaning to shorten.

Depending on context, it can mean things like:

• shorten a skirt or hem
• shorten a speech
• shorten a distance or time
• make something less long

In this sentence, because the object is faldinn (the hem), it clearly means shortening the hem of the skirt.

So the clothing meaning comes from the object, not from the verb alone.