Learn Hardcore Icelandic: Er það satt?

Er = is (3rd person singular of vera “to be”)
það = it/that (neuter pronoun in nominative)
satt = true (neuter nominative singular form of the adjective sannur “true”) Structure: Verb–Subject–Predicate adjective. The statement would be Það er satt. The yes/no question flips the verb to the front: Er það satt?

Why is the verb first in the question?

Icelandic forms yes/no questions by putting the finite verb first. Statement: Það er satt. Question: Er það satt? This is a standard pattern: verb-first for polar questions; in normal statements the verb is in second position (V2).

Why is it satt and not sannur or sönn?

Adjectives agree with the grammatical gender and case of the subject. það is neuter nominative, so the adjective is neuter nominative: satt. With other pronouns:

Hann er sannur. (masc.)
Hún er sönn. (fem.)
Það er satt. (neut.)

Can I say Er þetta satt? instead? What’s the difference between það and þetta?

Both are possible:

það often refers to something previously mentioned or more abstract/remote (like a claim or rumor).
þetta is more deictic/“this,” often for something immediate or just presented. In many contexts they overlap, and both will sound natural.

How do I pronounce it?

Approximate IPA: [ɛr θaːð saht]

þ = unvoiced “th” as in English “thing.”
ð = voiced “th” as in English “this.” In það, the final ð may be weak or dropped phrase-finally; before a following vowel it’s clearly pronounced (e.g., það er → [θaːð ɛr]).
tt in Icelandic has preaspiration, so satt is like [saht], with a short vowel (double consonant shortens the vowel). það has a long vowel [aː].
Yes/no questions typically have a slight rise in intonation at the end.

How do I answer this question naturally?

Affirmative: Já, það er satt. (Yes, that’s true.)
Negative: Nei, það er ekki satt. (No, that isn’t true.) If the question is negative, e.g., Er það ekki satt?, use Jú to contradict the negation: Jú, það er satt.

Can I drop það and just ask Er satt? Or just say Satt?

In full sentences you keep the subject: Er það satt? Informally, people do use the elliptical Satt? (“Really?/True?”) in conversation or messages. But Er satt? without a subject is not standard.

Is there a difference between satt and rétt?

Yes:

satt = true in the sense of truthfulness. Er það satt? asks whether the claim is true.
rétt = correct/right in the sense of accuracy or being the right answer. Er það rétt? is common when checking facts, calculations, or correctness. Often both can work, but nuance differs.

What case is satt in, and why?

Nominative. With the verb vera (“to be”), the predicate adjective/noun agrees with the subject in case, number, and gender. Since það is nominative neuter singular, you get satt.

How would I say this in other tenses?

Past: Var það satt? (Was that true?)
Present perfect: Hefur það verið satt? (Has that been true?)
Future (with munu): Mun það vera satt? (Will that be true?)
Note: Verður það satt? literally means “Will it become true?” which can imply a change from not-true to true.

What’s the present-tense conjugation of vera (“to be”)?

ég er
þú ert
hann/hún/það er
við erum
þið eruð
þeir/þær/þau eru

How can I type þ and ð?

Add the Icelandic keyboard layout on your device (recommended). Then þ and ð have dedicated keys. Without that, use your OS’s character/emoji viewer or copy–paste. Using th/dh is only an approximation; in proper Icelandic writing you should use þ and ð.