Ég á líka eftir að sópa svalirnar með kústi áður en gestirnir koma.

This is the very common Icelandic pattern eiga eftir að + infinitive.

It does not mean literal ownership here. It means something like:

• to still have left to do
• to still need to do
• to have yet to do

So Ég á líka eftir að sópa svalirnar... means roughly I also still have to sweep the balcony/balcony area...

The word líka adds also / too.

Grammatically, á is the present-tense form of eiga, which often does mean own or have.

But in this sentence, á is part of the idiom eiga eftir að. In that idiom, it does not mean literal possession.

So:

• Ég á bíl = I own/have a car
• Ég á eftir að fara = I still have to go / I have yet to go

Same verb, different meaning because of the full expression.

Because eiga eftir að is a fixed construction, and the að introduces the infinitive verb that follows.

Here:

• á eftir að sópa = have left to sweep

So sópa is in the infinitive, and að is the infinitive marker.

This is different from gestirnir koma, where koma is a finite verb in a clause, not an infinitive. That is why there is no að there.

That is a normal place for short adverbs in Icelandic.

The sentence starts with the subject:

• Ég

Then comes the finite verb:

• á

Then an adverb:

• líka

So Ég á líka eftir að... is very natural word order.

In English, learners often expect adverbs to behave differently, but Icelandic frequently places them after the finite verb.

Here líka most naturally means also / too, not still. The sense of still left to do already comes from á eftir að.

Svalirnar is the definite form of svalir.

A very important thing to know is that svalir is normally a plural noun in form in Icelandic, even when English might use singular balcony.

So:

• svalir = balcony / balconies
• svalirnar = the balcony / the balconies

In real usage, svalirnar often corresponds to English the balcony, even though the Icelandic word is morphologically plural.

Because the sentence is talking about the balcony/balcony area, not just a balcony.

Icelandic usually adds the definite article as a suffix to the noun.

So:

• svalir = balcony / balconies
• svalirnar = the balcony / the balconies

That ending -nar is the definite article here.

Here svalirnar is the direct object of sópa, so it is in the accusative.

The verb sópa typically takes the thing being swept in the accusative:

• sópa gólfið = sweep the floor
• sópa svalirnar = sweep the balcony

Because svalir happens to be a plural-form noun, the object appears as svalirnar.

Because the preposition með normally takes the dative case when it means with.

The dictionary form is:

• kústur = broom

But after með, it changes to dative singular:

• með kústi = with a broom

So this is a case-governed form:

• nominative: kústur
• dative: kústi

Good question. Sópa already tells you the action is sweeping, so með kústi is not strictly necessary for basic meaning.

But it can still be added to:

• be more specific
• emphasize the tool used
• contrast with another method of cleaning

For example, it may imply with a broom, not with some other tool.

So the sentence without it would still work:

• Ég á líka eftir að sópa svalirnar áður en gestirnir koma.

Adding með kústi just gives extra detail.

Áður en means before.

It introduces a subordinate clause:

• áður en gestirnir koma = before the guests come

So the structure is:

• main clause: Ég á líka eftir að sópa svalirnar með kústi
• subordinate time clause: áður en gestirnir koma

This is a very common way to talk about something that must happen before another event.

Icelandic often uses the present tense to refer to the future, especially in time clauses like this one.

So:

• áður en gestirnir koma literally looks like before the guests come
• but in meaning it can be before the guests arrive / before the guests come

Using munu koma is possible in some contexts, but it is less natural here. After time expressions such as áður en, the simple present is very common for future meaning.

English does something similar:

• before the guests come not usually
• before the guests will come

It comes from:

• gestir = guests
• -nir = the definite article ending for this form

So gestirnir means the guests.

In this clause, gestirnir is the subject, so it is in the nominative plural.

Yes, you could, and it would be perfectly understandable.

But there is a nuance:

• Ég þarf að sópa... = I need to sweep...
• Ég á eftir að sópa... = I still have to sweep... / I haven’t gotten around to sweeping yet

So á eftir að often suggests an unfinished task that remains to be done. It has a slightly stronger sense of this is still pending.

That is why it is especially natural here.

The given order is neutral and natural, but Icelandic word order can change for emphasis.

For example, you could also say:

• Áður en gestirnir koma, á ég líka eftir að sópa svalirnar með kústi.

That puts the time clause first: Before the guests come...

You can also front other elements for emphasis, but then Icelandic follows its verb-second pattern in the main clause.

So the original sentence is a good basic model, even though other word orders are possible.

A useful breakdown is:

• Ég = I
• á líka eftir að = also still have left to / also still have to
• sópa = sweep
• svalirnar = the balcony / the balconies
• með kústi = with a broom
• áður en gestirnir koma = before the guests come

So the whole structure is:

subject + idiomatic verb phrase + infinitive + object + prepositional phrase + time clause

That makes this sentence a very good example of how Icelandic builds meaning through:

• fixed expressions
• case after prepositions
• the suffixed definite article
• present tense with future meaning in a subordinate clause