Tímamælirinn byrjar núna.

In Icelandic, the definite article is usually attached to the end of the noun instead of written as a separate word.

• tímamælir = timer
• tímamælirinn = the timer

So -inn is the masculine singular definite ending here. English uses a separate word, the, but Icelandic often builds that meaning into the noun itself.

The basic dictionary form is tímamælir.

That is the indefinite singular form, meaning a timer or just timer.
In this sentence, it appears as tímamælirinn, the definite form, because the meaning is the timer.

Yes. Tímamælirinn is the subject of the sentence, so it is in the nominative case.

This is very normal in Icelandic:

• subject = usually nominative
• verb agrees with the subject in person and number

Here the subject is singular, and the verb is also singular: byrjar.

Byrjar comes from the verb byrja, which means to begin or to start.

In this sentence, byrjar is:

• present tense
• 3rd person singular

So it means begins or starts.

A few related forms:

• að byrja = to begin / to start
• ég byrja = I begin / I start
• hann/hún/það byrjar = he/she/it begins

That ending is part of how this verb is conjugated in the present tense.

For byrja, the present tense goes like this:

• ég byrja
• þú byrjar
• hann/hún/það byrjar
• við byrjum
• þið byrjið
• þeir/þær/þau byrja

Because tímamælirinn is a singular it, Icelandic uses the same form as hann/hún/það: byrjar.

Here it is used intransitively, meaning the subject itself is beginning.

So Tímamælirinn byrjar núna means that the timer itself starts now.

But byrja can also appear with an object or with another verb, depending on context. For example:

• Ég byrja núna. = I’m starting now.
• Ég byrja leikinn. = I start the game.
• Ég byrja að lesa. = I start reading.

Both can mean now, but núna often feels a bit more like right now / at this moment, while nú can be slightly broader or more neutral depending on context.

In everyday speech, núna is very common.

So in this sentence, núna gives a clear sense of immediacy:

• byrjar núna = starts now / starts right now

In many contexts, nú would also be possible, but núna sounds very natural here.

Yes, Icelandic word order is somewhat flexible, but the most neutral order here is:

• Tímamælirinn byrjar núna.

You may also see other orders for emphasis, especially in real speech or more complex sentences. For example, putting núna earlier could emphasize the timing more strongly.

Still, for a learner, this sentence is a good basic pattern:

• subject + verb + time word

A few useful points:

• Stress in Icelandic normally falls on the first syllable, so the main stress is on TÍma-.
• í is a long ee-like sound.
• á is not the same as English a; it has its own Icelandic vowel sound.
• byrjar begins with b, but Icelandic consonants may sound a little different from English depending on position and accent.
• núna is usually straightforward for learners once they know ú is a long vowel.

You do not need perfect pronunciation immediately, but it helps to remember: first-syllable stress is very important in Icelandic.

Because Icelandic usually expresses the by adding an ending to the noun.

So instead of:

• the timer

Icelandic often uses:

• tímamælirinn

This is one of the first big structural differences English speakers notice. Icelandic does have ways to use a separate demonstrative word in some contexts, but the ordinary definite article is usually attached to the noun.

Yes. It is short, clear, and completely natural.

It works well in contexts like:

• starting a countdown
• beginning a timed activity
• announcing that a timer is starting immediately

It is also a good beginner sentence because it shows several important Icelandic patterns at once:

• a definite noun with the article attached
• a present-tense verb
• a common time adverb
• normal basic word order