Sonurinn er ungur og dóttirin er líka ung.

The ending -urinn is the definite article attached to the noun.

• sonur = a son
• sonurinn = the son

In Icelandic, “the” is usually not a separate word. Instead, it is added to the end of the noun as a suffix:

• masculine nominative singular often ends in -inn / -urinn
  
  • hestur → hesturinn (the horse)
  • sonur → sonurinn (the son)

Because dóttir (daughter) is feminine, and the feminine definite ending in the nominative singular is -in, not -inn.

• dóttir = a daughter
• dóttirin = the daughter

So:

• masculine: sonur → sonurinn (the son)
• feminine: dóttir → dóttirin (the daughter)

The spelling change is mostly about how Icelandic attaches endings. You don’t say dóttirinn; that would be considered wrong in standard Icelandic.

er is the 3rd person singular present form of the verb vera = to be.

Present tense of vera:

• ég er – I am
• þú ert – you are (singular, informal)
• hann / hún / það er – he / she / it is
• við erum – we are
• þið eruð – you are (plural)
• þeir / þær / þau eru – they are

So:

• Sonurinn er ungur = The son is young
• Dóttirin er ung = The daughter is young

They both mean “young”, but in Icelandic adjectives change form to agree with the noun in:

• gender (masculine / feminine / neuter)
• number (singular / plural)
• case (nominative, etc.)

Here:

• sonurinn is masculine singular nominative

  • → adjective: ungur (masculine singular nominative)
  • Sonurinn er ungur.

• dóttirin is feminine singular nominative

  • → adjective: ung (feminine singular nominative)
  • Dóttirin er ung.

So the base meaning is the same, but the form of the word “young” changes to match the noun.

Because in this sentence “young” is part of the predicate, not an adjective directly modifying a noun.

• Sonurinn er ungur.
  Literally: The son is young.
  Structure: [Subject] [verb “to be”] [adjective]

If you want “the young son” as a noun phrase, Icelandic normally puts the adjective before the noun, with different endings:

• ungi sonurinn = the young son
• unga dóttirin = the young daughter

So:

• After er (predicative): sonurinn er ungur
• Before the noun (attributive): ungi sonurinn

You can certainly combine them into one clause, but the form of the adjective must match a mixed-gender plural subject.

• Sonurinn og dóttirin eru ungir.
  = The son and the daughter are young.

Explanation:

• The subject “sonurinn og dóttirin” is plural and includes a masculine noun.
• In Icelandic, a mixed group (masculine + feminine) uses the masculine plural adjective:
  • masculine plural of ungur is ungir.

So:

• Correct: Sonurinn og dóttirin eru ungir.
• Incorrect: Sonurinn og dóttirin eru ung (wrong form).

The original sentence simply chooses to repeat the verb and adjective:

• Sonurinn er ungur og dóttirin er líka ung.
  The son is young and the daughter is also young.

Both are forms of vera (to be), but:

• er = singular (is)
• eru = plural (are)

Examples:

• Sonurinn er ungur. – The son is young.
• Dóttirin er ung. – The daughter is young.
• Sonurinn og dóttirin eru ungir. – The son and the daughter are young.

So you use er for one subject, and eru for they / several things.

líka means “also / too / as well.”

In this sentence:

• Sonurinn er ungur og dóttirin er líka ung.
  = The son is young, and the daughter is also young.

Typical placements for líka:

• After the verb:
  
  • Hann er líka þreyttur. – He is also tired.
• After the subject (still usually early in the sentence):
  
  • Hún líka er þreytt. – She also is tired. (more emphasis on she as the one who also is)

Here líka comes after “er”, which is very natural and common.

og means “and”.

The basic word order on both sides of og is usually Subject – Verb – Rest, very similar to English:

• Sonurinn er ungur – The son is young
• og – and
• dóttirin er líka ung – the daughter is also young

So the structure is:

• [Subject] [er] [adjective] og [Subject] [er] [líka] [adjective].

Word order in simple Icelandic main clauses is usually SVO, like in English.

Very rough English-based approximations (not precise IPA, just to give a feel):

• Sonurinn – roughly: SOH-nu-rin

  • so as in so
  • nu like new but very short, almost nuh
  • final -rin like rin in rinse without the s

• er – roughly: air but shorter

• ungur – roughly: OONG-gur

  • u like oo in book (but a bit different)
  • ng as in sing
  • ur like a short oor with a tapped r

• og – roughly: somewhere between oh and og

  • often pronounced like “og” with a very soft or almost lost g depending on dialect and speed

• dóttirin – roughly: DOH-ttir-in

  • dó like dough
  • ttir: double t is pronounced sharply, and -ir is like ear but shorter and closer
  • final -in like in in in

• líka – roughly: LEE-ka

  • lí like lee
  • ka like kah

For accurate pronunciation, listening to native speakers or a TTS engine for Icelandic is essential.

• sonur / sonurinn is masculine.
• dóttir / dóttirin is feminine.

Gender matters because:

1. It affects the definite endings:

   • masculine: -inn / -urinn → sonurinn
   • feminine: -in → dóttirin

2. It affects adjective agreement:

   • masculine: ungur → Sonurinn er ungur.
   • feminine: ung → Dóttirin er ung.

So to form correct Icelandic, you must learn each noun’s grammatical gender and let adjectives and endings agree with it.