Trefillinn hans er grænn en húfan er blá.

to be

Breakdown of Trefillinn hans er grænn en húfan er blá.

• en: but
• grænn: green
• blár: blue
• hans: his
• trefillinn: the scarf
• húfan: the hat

Questions & Answers about Trefillinn hans er grænn en húfan er blá.

What does each Icelandic word in Trefillinn hans er grænn en húfan er blá correspond to in English?

• trefill = scarf
• -inn = the (masculine singular definite ending) → trefillinn = the scarf
• hans = his
• er = is
• grænn = green (masculine, singular, nominative form)
• en = but
• húfa = hat / cap
• -n = the (feminine singular definite ending) → húfan = the hat
• blá = blue (feminine, singular, nominative form)

Putting it all together: Trefillinn hans er grænn en húfan er blá = His scarf is green but the hat is blue.

Why is trefillinn used instead of just trefill?

Icelandic doesn’t use a separate word for the like English; instead, the definite article is a suffix.

• trefill = a scarf (indefinite)
• trefillinn = the scarf (definite)

So trefillinn literally means scarf-the.

Why does húfa become húfan?

Húfa is a feminine noun meaning hat or cap.
In the nominative singular, the definite form of many feminine -a nouns is made by adding -n:

• húfa = a hat
• húfan = the hat

So húfan means the hat.

Why is it Trefillinn hans and not hans trefill, like “his scarf” in English?

In normal, everyday Icelandic, possessive pronouns usually come after the noun:

• trefillinn hans = literally the scarf his

This is the most neutral way to say his scarf.
Hans trefill exists but sounds marked/poetic or is used for emphasis (more like his scarf (as opposed to someone else’s)).

Should it be Trefill hans or Trefillinn hans for “his scarf”? What’s the difference?

• trefill hans = a scarf of his / his (some) scarf (indefinite)
• trefillinn hans = his scarf with a specific scarf in mind (definite: the scarf of his)

In a context like this, where we’re talking about particular pieces of clothing, trefillinn hans (definite) is the natural choice.

Why is there no hans with húfan? How would I say “his hat” too?

The given sentence has:

• Trefillinn hans er grænn = His scarf is green
• en húfan er blá = but the hat is blue

The context makes it clear we’re still talking about his things, so Icelandic can omit hans in the second clause.
If you want to be explicit: Trefillinn hans er grænn en húfan hans er blá = His scarf is green but his hat is blue.

What does en mean here, and how is it different from og?

En means but and introduces a contrast:

• Trefillinn hans er grænn en húfan er blá = His scarf is green but the hat is blue.

Og means and and simply adds things together, without contrast:

• Trefillinn hans er grænn og húfan er blá = His scarf is green and the hat is blue (just stating two facts, not highlighting contrast).

Why is it grænn with trefillinn and blá with húfan? Why do the adjective endings change?

Adjectives in Icelandic agree with the noun in gender, number, and case.

• trefillinn is masculine singular nominative, so green appears as grænn (masc.sg.nom).
• húfan is feminine singular nominative, so blue appears as blá (fem.sg.nom).

So the color words change their endings to match the noun they describe.

Why are grænn and blá in the “strong” form and not græni, bláa, etc.?

In Icelandic, predicative adjectives (adjectives after the verb vera “to be”) normally use the strong declension:

• trefillinn hans er grænn (strong form)
• húfan er blá (strong form)

The weak forms like græni, bláa are used mostly when the adjective directly modifies a definite noun (the green scarf = græni trefillinn, the blue hat = bláa húfan).

What case are trefillinn hans and húfan in, and why?

Both trefillinn hans and húfan are in the nominative case.
The verb er (is) is a copula; it links the subject to a description, and the subject of such a verb is in the nominative:

• Trefillinn hans (nom.) er grænn (nom.)
• húfan (nom.) er blá (nom.)

So the nouns and the adjectives are all nominative here.

Can I leave out the second er and say Trefillinn hans er grænn en húfan blá?

No, that sounds ungrammatical or at least very odd in Icelandic.
You normally need to repeat er:

• Trefillinn hans er grænn en húfan er blá.

Omitting the repeated verb, which is common in English, is generally not done this way in Icelandic.

How are trefillinn and húfan pronounced, especially the double ll?

Approximate pronunciations (in simple English-friendly terms):

• trefillinn ≈ TREH-vit-lin
  
  • The ll is pronounced as a kind of t-l cluster; Icelandic ll often sounds like tl.
• húfan ≈ HOO-van
  
  • ú is a long oo sound, like in food.

These are approximations; actual Icelandic pronunciation has more precise sounds, but this will get you close.