Learn Hardcore Icelandic: Dagurinn er stuttur.

Icelandic doesn’t use a separate word for “the.” Instead, it shows definiteness by adding a suffix to the noun. The base form dagur means “a day” (indefinite), and dagurinn is “the day” (definite) with the suffix -inn.

What case and number is dagurinn, and why?

Dagurinn is in the nominative singular because it’s the subject of the sentence. Subjects in Icelandic (as in English) normally appear in the nominative case.

What form is the adjective stuttur, and how does it agree with dagurinn?

Stuttur is the masculine nominative singular (strong) form of the adjective “short.” In predicate position (after the verb vera), adjectives agree with their subject in gender, number, and case—here matching the masculine nominative singular dagurinn.

Why isn’t the adjective in the weak (definite) form stutti?

Adjectives following the copula vera (“to be”) use the strong (indefinite) declension, even if the noun is definite. The weak form stutti would only appear if the adjective were used attributively with a definite noun (e.g. í stutta daga “in the short days”).

Why is the verb er placed between dagurinn and stuttur?

Icelandic follows the V2 (verb‐second) word order. When the subject dagurinn comes first in the clause, the finite verb er must follow it in second position, and then the predicate adjective stuttur comes third.

How would you turn this into a yes/no question: “Is the day short?”

Simply invert the verb and the subject:
Er dagurinn stuttur?

How would you say “This day is short” in Icelandic?

Add the demonstrative Þessi (this) before dagur, keeping the rest the same:
Þessi dagur er stuttur.

How do you pronounce Dagurinn er stuttur?

Rough phonetic guide using English sounds:
DAH-goo-rin er STOOT-tur
• DAH-goo-rin – stress on the first syllable; g as in “go,” the double -nn is a single sound
• er – like English “air” but shorter
• STOOT-tur – oo as in “boot,” tt is a long (geminate) [tː] sound