Ekki stela peningunum.

That is one of the most important things to notice here.

In Icelandic, negative commands are very often made with:

ekki + infinitive

So:

• Ekki stela = Don’t steal
• literally, it looks like not to steal, but functionally it means don’t steal

This is a very common and natural way to tell someone not to do something.

So even though English uses don’t + base verb, Icelandic often uses ekki + infinitive instead of a special negative imperative form.

Ekki means not.

In this sentence, it comes first because the whole sentence is a negative command:

• Ekki stela ... = Don’t steal ...

Putting ekki first is the normal pattern here. It immediately tells you that the speaker is prohibiting something.

So the structure is:

• Ekki = don’t / not
• stela = steal
• peningunum = the money

Because the verb stela requires the thing stolen to be in the dative case.

So Icelandic does not say:

• stela peningana for this meaning

Instead it says:

• stela peningunum

That is because stela governs the dative object.

A very useful dictionary-style pattern is:

• stela einhverju = to steal something

So when you learn stela, it is best to learn it together with its case pattern:

• stela + dative

Peningunum is the definite dative plural form of peningar.

You can break it down like this:

• peningar = money / coins (plural base form)
• peningum = money / coins in the dative plural
• peningunum = the money / the coins in the dative plural

So this one word contains both:

• the noun
• the case ending
• the definite article

That is why it looks longer than the English word money.

There is no separate word for the here, because Icelandic usually attaches the definite article to the end of the noun.

So:

• peningum = money / coins in dative plural
• peningunum = the money / the coins in dative plural

In other words, the the is built into peningunum.

This is very common in Icelandic. Instead of a separate word like English the, Icelandic often uses a noun ending.

Yes, peningunum is grammatically plural.

That can feel a little strange, because English usually treats money as an uncountable noun. But Icelandic often uses peningar in the plural where English simply says money.

So depending on context, peningunum can correspond to:

• the money
• the coins
• the cash

Even though the Icelandic form is plural, the natural English translation is often just the money.

This form does not clearly mark the number of the person being addressed.

With ekki + infinitive, the command is fairly general, so it can be used to:

• one person
• more than one person
• a general audience, like on a sign or notice

So Ekki stela peningunum can work as:

• a direct warning to one person
• a prohibition said to a group
• a general instruction

English does something similar with Don’t steal the money, which also does not change form for singular vs. plural you.

Yes. It is short, direct, and natural as a prohibition.

It sounds like:

• an order
• a warning
• a command
• a line in dialogue
• a notice telling someone not to do something

Because it is so short, it can sound quite strong or blunt, just like English Don’t steal the money.

Because commands normally leave the subject unstated.

Just as English says:

• Don’t steal the money rather than
• You, don’t steal the money

Icelandic also normally omits the subject in commands.

The you is understood from the context.

A rough learner-friendly pronunciation is:

EH-kih STEH-la PEH-ning-un-um

A few helpful points:

• Stress in Icelandic usually falls on the first syllable of each word.
• Ekki sounds roughly like EH-kih
• stela sounds roughly like STEH-la
• peningunum has the stress at the start: PEH-ning-un-um

This is only an approximate English-style guide, but it is enough to help you start saying the sentence aloud.