Learn Hardcore Icelandic: Sólin skín í dag.

Sólin is the definite form, meaning “the sun.” In Icelandic, the definite article is a suffix rather than a separate word. The base noun sól means “sun,” and adding -in (the feminine singular article) gives sólin = “the sun.”

What is the infinitive of skín, and what tense/person is this form?

The infinitive is skína (to shine). The form skín is present indicative, 3rd person singular — he/she/it shines.

Why is í dag used for “today” instead of dagur or dagurinn?

í dag is a fixed time‐expression meaning “today.”

dagur is the bare noun “day” (nominative singular).
dagurinn is “the day” (definite nominative).
When telling time with í, you use the accusative form dag without the article. If you wanted “during the day,” you would say í daginn (accusative definite).

What case is dag in í dag?

It’s the accusative singular of dagur. When í expresses time, it generally takes the accusative case in Icelandic.

Can I say Í dag skín sólin instead? Does the order matter?

Yes. Icelandic main clauses obey the V2 rule: the finite verb must be second. If you front í dag, the verb skín follows, then the subject sólin. Both Sólin skín í dag and Í dag skín sólin are correct; the latter simply puts more emphasis on today.

Why isn’t there a subject pronoun like hún for sólin?

Icelandic often drops subject pronouns because the verb ending already shows person and number. You could say Sólin skín í dag, en hún rigndi í gær (“The sun is shining today, but it rained yesterday”), but in simple statements the pronoun is usually omitted.

How do I pronounce Sólin skín í dag?

Roughly:

SÓL-in (like “sole-in” but with a long ó)
SKEEN (long í)
ee (short í)
DAHG (the a is like the “a” in “father”)

So altogether: SÓL-in SKEEN ee DAHG.

What gender is sól, and how do I know?

sól is feminine. In Icelandic you usually have to learn the gender of each noun, though many feminine nouns end in -a or -l. The definite suffix -in confirms that sól is feminine singular.