Learn Hardcore Icelandic: Klukkan slær tólf á miðnætti.

Klukkan is the definite nominative singular of klukka (“clock”). Icelandic marks the definite article by adding an ending (–n for feminine nouns like klukka). Here it literally means “the clock.”

What does the verb slær mean, and what is its infinitive?

slær is the 3rd person singular present tense of slá (“to strike,” “to hit”). In this sentence, klukkan slær means “the clock strikes.”

Why is tólf not inflected? How do Icelandic numerals work here?

tólf (“twelve”) is a cardinal number that remains unchanged when used as the object of slá. After certain verbs and in telling time, cardinal numbers typically stay in their base form.

Why is á used before miðnætti, and what case does miðnætti take?

The preposition á takes the dative when indicating a point in time. Therefore, miðnætti is the dative singular of miðnætti (“midnight”).

Can you front the time expression in this sentence? If so, how?

Yes. Icelandic follows a verb-second (V2) word order. If you start with the time phrase, the verb comes next, then the subject: Á miðnætti slær klukkan tólf.

How would you say “by midnight” instead of “at midnight”?

Use fyrir + accusative for a deadline: fyrir miðnætti
Here miðnætti remains unchanged (neuter accusative = neuter nominative).

Why does miðnætti have a double t?

Doubling the consonant signals that the preceding vowel æ is short. The root is miðnæt-, so when the dative ending -i is added, the t is geminated to maintain proper vowel length.