Sonurinn er núna á sama aldri og vinkona hans í skólanum.

Icelandic usually shows definiteness with a suffixed article instead of a separate word like the.

• sonur = a son / son (indefinite)
• sonurinn = the son (definite)

So sonurinn means a specific son that both speaker and listener know about (e.g. their son, my son). English needs the, but Icelandic sticks -inn onto the noun instead.

The neutral word order is:

subject – verb – time adverb – other information
Sonurinn er núna á sama aldri…

So er núna is the most natural order.

You can move núna for emphasis:

• Núna er sonurinn á sama aldri… (strong emphasis on now)
• Sonurinn er á sama aldri núna… (a bit marked, but possible)

But Sonurinn núna er… sounds wrong; adverbs like núna should not usually go between the subject and the verb in this simple sentence.

Two things are going on:

1. The preposition á (in this abstract sense: at a certain age) takes the dative case.
2. The noun aldur (age) in the dative singular is aldri.

Declension (singular):

• Nom: aldur
• Acc: aldur
• Dat: aldri
• Gen: aldurs

So after á (here: in/at a state), we need the dative:

• á aldri → á sama aldri

That’s why you see aldri, not aldur.

sami is the Icelandic word for same, and it declines (changes form) for gender, number, and case.

Here it is:

• modifying a masculine singular noun: aldur
• in the dative case (because of á)

Dative singular masculine of sami is sama:

• Nom m. sg.: sami
• Acc m. sg.: sama
• Dat m. sg.: sama
• Gen m. sg.: sama

So á sama aldri = at the same age, with sama matching aldri in case, number, and gender.

In this structure og functions like as in English comparisons.

Pattern:

• á sama X og Y = (to be) the same X as Y

So:

• á sama aldri og vinkona hans
  literally: at the same age as his friend

The same happens with adjectives:

• hann er jafn gamall og hún = he is as old as she is

So here og is not and but comparative as.

Both orders are grammatically possible, but they differ in usualness and emphasis.

• vinkona hans = his (female) friend
  This is the neutral, most common order: noun + possessive.

• hans vinkona
  This places extra emphasis on hans (his friend, as opposed to someone else’s). It can also sound slightly more formal or literary, depending on context.

In everyday speech and writing, vinkona hans is the normal choice.

Icelandic has two types of 3rd person possessives:

1. hans / hennar / þeirra – ordinary 3rd person possessives
2. sinn / sín / sitt – reflexive possessive (refers back to the subject of the same clause)

In this sentence:

• subject: sonurinn (3rd person)
• possessive: hans (his)

Technically, since the possessor is the subject, sín could appear in another structure, but:

• vinkona hans is the normal wording.
• Using sín here (vinkona sín) would sound wrong or very odd, because sinn/sín/sitt is usually used when the possessor is the subject and the phrase is more clearly reflexive (e.g. loves his own mother etc.).

So hans is correct and natural: vinkona hans = his (female) friend.

vinur = friend (usually masculine form)
To specify a female friend, Icelandic often adds -kona (woman) to a masculine base:

• vinur → vinkona = female friend

So:

• vinur hans = his (male) friend
• vinkona hans = his (female) friend

vinkona is a feminine noun, which is why it ends in -a in the nominative singular.

Three issues: preposition meaning, case, and definiteness.

1. Location vs movement with í:
   • Static location (in/at): í
     • dative
   • Movement into: í
     • accusative

Here we mean at school (location), so we use the dative.

2. Declension of skóli (school), singular:
   • Nom: skóli
   • Acc: skóla
   • Dat: skóla
   • Gen: skóla

With the definite article:

• Nom: skólinn
• Acc: skólann
• Dat: skólanum
• Gen: skólans

So dative definite is skólanum.

3. Definiteness and idiom:
   • í skóla = in (a) school / in school (more generic)
   • í skólanum = in the school / at school (specific or idiomatic)

In everyday Icelandic, í skólanum often just means at school (not necessarily one specific building the way English “the school” might sound).

So í skólanum is natural here: at school.

By default, í skólanum most naturally attaches to vinkona hans:

• vinkona hans í skólanum ≈ his (female) friend at school / his school friend

If the intended meaning were the son is now, at school, the same age as his friend, you would usually restructure or add something for clarity.

So the usual reading is:

The son is now the same age as his friend at school.

Yes. Grammar stays the same; you just lose the explicit “now”:

• Sonurinn er á sama aldri og vinkona hans í skólanum.

This simply states a fact, often understood as currently true from context.
Adding núna highlights the contrast with some previous time:

• Sonurinn er núna á sama aldri… = He now is the same age (but earlier he wasn’t).

Yes, a very common alternative uses jafn gamall og:

• Sonurinn er núna jafn gamall og vinkona hans í skólanum.
  = The son is now as old as his friend at school.

Two main patterns:

1. á sama aldri og X
2. jafn gamall og X (for males; jafn gömul og for females)

Both are natural; á sama aldri og is slightly more neutral and noun-based (age), while jafn gamall og is adjective-based (old).

Yes, that is correct and quite natural.

• Sonurinn er núna á sama aldri… – neutral, time adverb after the verb.
• Núna er sonurinn á sama aldri… – puts stronger emphasis on núna (right now).

Both are fully grammatical. The choice is about which element you want to stress.