Eftir súpuna pöntum við eftirrétt, því stelpan vill eitthvað sætt.

Not exactly.

• In Eftir súpuna, eftir is a preposition meaning after.
• In eftirrétt, eftir is part of a compound noun, literally something like after-course or after-dish, meaning dessert.

So the same word appears twice, but it has two different grammatical roles. Icelandic makes a lot of compound words like this.

This is because Icelandic normally follows a verb-second pattern in main clauses.

If the sentence begins with something other than the subject, the finite verb usually comes next:

• Við pöntum eftirrétt. = We order dessert.
• Eftir súpuna pöntum við eftirrétt. = After the soup, we order dessert.

So Eftir súpuna takes the first slot, and pöntum must come second. Then the subject við comes after the verb.

Súpuna is not the basic dictionary form. It is the form meaning the soup in this sentence.

It shows that the noun is:

• definite: the soup
• in the case used after eftir here

So:

• súpa = soup
• súpuna = the soup

This is very common in Icelandic: the noun changes form depending on grammar, not just meaning.

Eftirréttur is the nominative singular form, the one you usually see in a dictionary.

In this sentence, the word is the direct object of pöntum, so it appears in the accusative singular:

• eftirréttur = dessert (dictionary form)
• eftirrétt = dessert (object form used here)

Many masculine nouns lose -ur outside the nominative singular, so this pattern is very normal.

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

For example:

• stelpa = girl
• stelpan = the girl
• súpa = soup
• súpuna = the soup

The exact ending changes depending on gender, number, and case, so the article does not always look the same.

Icelandic does not have an indefinite article like English a/an.

So a bare noun can mean:

• a dessert
• or just dessert

depending on context.

That means eftirrétt here naturally means a dessert or dessert. If you wanted the dessert, you would use the definite form instead.

In this sentence, því is a conjunction meaning because, since, or sometimes for.

So:

• því stelpan vill eitthvað sætt = because the girl wants something sweet

Learners often also see af því að, which is another common way to say because. Here, því is just the conjunction linking the reason to the first clause.

Because eitthvað is grammatically neuter singular, and the adjective has to agree with it.

The adjective sætur means sweet, but here it becomes sætt, the neuter singular form:

• eitthvað sætt = something sweet

This is a very common Icelandic pattern:

• eitthvað gott = something good
• ekkert nýtt = nothing new
• allt rétt = everything right/correct

Even though English does not show this kind of agreement, Icelandic does.

They are present-tense verb forms.

• pöntum is from panta = to order
  • við pöntum = we order
• vill is from vilja = to want
  • stelpan vill = the girl wants

So the sentence contains:

• pöntum við = we order
• stelpan vill = the girl wants

Also, the -um ending in pöntum marks first person plural (we). The vowel change from a to ö is a normal pattern in many Icelandic verb forms.