Merktu svarið.

Merktu is the singular imperative of the verb merkja. In other words, it is the form used when giving a command to one person: Mark ...

If you were telling more than one person, you would normally use merkið instead:

• Merktu svarið. = command to one person
• Merkið svarið. = command to more than one person

In Icelandic, as in English, commands usually leave out the subject. The you is understood.

So:

• Merktu svarið. = Mark the answer.
• Adding þú would sound marked or emphatic, not neutral.

This is completely normal for the imperative.

Svarið is made of:

• svar = answer
• -ið = the definite article for a neuter singular noun

So svarið literally means the answer.

A very important Icelandic feature is that the definite article is often attached to the end of the noun, instead of being a separate word like English the.

Here svarið is the direct object of the verb merkja, so it is in the accusative.

However, with many neuter nouns in Icelandic, the nominative and accusative singular look the same. So even though it is accusative here, the form is still svarið.

That is why the sentence looks simple on the surface, even though case is still involved.

This is part of how many Icelandic singular imperatives are formed.

A useful way to think about it here is:

• present form: ég merki
• remove the final -i
• add the imperative ending, which here appears as -tu

So:

• merki → merk
  • tu → merktu

The -tu form is normal here because of the sound environment after k.

No. Merkja has a range of meanings, and the exact sense depends on context. It can mean things like:

• mark
• label
• indicate
• note
• tick/check

In exercise or test instructions, it often means something like mark, select, or tick the answer.

That is the normal word order for a simple imperative in Icelandic:

• verb + object

So:

• Merktu svarið.

This is the straightforward way to give a command. English does the same thing:

• Mark the answer.

Yes, sometimes. Icelandic instructions often use merkja við when the idea is specifically tick/check/select an option, especially on worksheets or tests.

For example:

• Merktu við rétt svar. = Mark/tick the correct answer.

Without við, merkja can still mean mark or label something directly. So Merktu svarið is grammatical, but the exact classroom-style nuance may vary depending on context.

A rough guide is:

• Merktu ≈ MERK-tuh
• svarið ≈ SVA-rith

A few helpful pronunciation points:

• Icelandic stress is usually on the first syllable.
• The r is typically a tapped or trilled r.
• ð is like the th in this, though at the end of a word it can sound quite light.

So the main stress pattern is:

• MERKtu SVArið