Ef straujárnið er of heitt, verður skyrtan ekki sléttari heldur verri.

Here of means too.

So:

• of heitt = too hot

This is a very common beginner trap because it looks like the English word of, but it is completely different in meaning.

Examples:

• of kalt = too cold
• of dýrt = too expensive
• of seint = too late

So straujárnið er of heitt means the iron is hotter than it should be.

Ef means if and introduces a condition.

So the first part:

• Ef straujárnið er of heitt = If the iron is too hot

This is a subordinate clause. In Icelandic, when a subordinate clause like this comes first, it affects the word order in the main clause that follows.

This is because of Icelandic V2 word order.

When the sentence begins with something other than the main-clause subject — here, the whole ef-clause — the finite verb of the main clause usually comes next.

So the structure is:

• Ef straujárnið er of heitt, verður skyrtan ...

Literally, this is something like:

• If the iron is too hot, becomes the shirt ...

That sounds odd in English, but it is normal in Icelandic.

If you put the main clause first, you would normally get:

• Skyrtan verður ekki sléttari heldur verri ef straujárnið er of heitt.

Then the subject comes before the verb as you might expect.

These are the suffixed definite articles, meaning the.

In Icelandic, the is usually attached to the end of the noun rather than written as a separate word.

So:

• straujárn = iron
• straujárnið = the iron

and

• skyrta = shirt
• skyrtan = the shirt

The different endings reflect the gender and form of the noun.

Because heitt agrees with straujárnið, which is neuter singular.

The adjective heitur changes form depending on gender:

• masculine: heitur
• feminine: heit
• neuter: heitt

Since straujárnið is neuter, Icelandic uses:

• straujárnið er of heitt

This is standard adjective agreement.

Here verður is best understood as becomes or ends up being.

It is the present tense of verða, a very common verb that can mean things like:

• become
• happen
• come to be

In this sentence, it describes a change in result:

• the shirt does not become smoother
• it becomes worse

So this is not just a simple is sentence. It is about what happens as a result of the iron being too hot.

Because the sentence is comparing two possible results.

• sléttari = smoother
• verri = worse

The idea is:

• the shirt does not become smoother
• it becomes worse instead

In Icelandic, comparatives are very common after verbs like verða when you describe how something changes.

So:

• verða sléttari = become smoother
• verða verri = become worse

Ekki ... heldur ... is a very common pattern meaning:

• not ... but rather ...

So:

• ekki sléttari heldur verri

means:

• not smoother, but worse

This is the natural negative contrast pattern in Icelandic.

You can think of heldur here as meaning something like rather or instead after a negation.

So the logic is:

• not X
• but Y instead

Yes. Verri is an irregular comparative meaning worse.

It does not look as simple as regular comparatives such as:

• sléttur → sléttari

By contrast:

• verri = worse

So this is a form you mainly just have to learn and recognize.

It is a very common word, so it is worth memorizing early.

Yes. They describe skyrtan, so they agree with it as predicate adjectives.

In this sentence, skyrtan is the subject of the main clause, and the adjectives tell us what state it becomes:

• skyrtan verður sléttari
• skyrtan verður verri

So even though they come after verður, they still refer back to skyrtan.

A useful way to think about it is:

• skyrtan = the thing being described
• sléttari / verri = the description of what it becomes

Yes. You can say:

• Skyrtan verður ekki sléttari heldur verri ef straujárnið er of heitt.

This has essentially the same meaning.

The main difference is word order:

• when the ef-clause comes first, the main-clause verb comes before the subject: verður skyrtan
• when the main clause comes first, you get the more basic order: skyrtan verður

So this sentence is also a good example of how Icelandic word order changes depending on what comes first.

Because Icelandic usually expresses the by attaching it to the noun.

That is why you see:

• straujárnið = the iron
• skyrtan = the shirt

English uses a separate article:

• the iron
• the shirt

Icelandic usually does not. This is one of the biggest structural differences from English, and this sentence shows it clearly with both nouns.