Achttien gasten komen.

Because the subject is plural: achttien gasten = eighteen guests.

In the present tense, Dutch uses:

• komt for singular hij/zij/het or a singular noun
• komen for plural subjects

So:

• De gast komt. = The guest is coming.
• De gasten komen. = The guests are coming.
• Achttien gasten komen. = Eighteen guests are coming.

Dutch usually works like English here: when you use a number directly before a noun, you normally do not add an article.

So:

• achttien gasten = eighteen guests
• not een achttien gasten
• not de achttien gasten, unless you mean the eighteen guests specifically

If you do say de achttien gasten, that means a particular group of eighteen guests already known from the context.

In a normal Dutch main clause, the finite verb usually comes in the second position.

Here:

• Achttien gasten is the first element
• komen is the finite verb, so it comes second

So the structure is:

• [subject phrase] + [finite verb]
• Achttien gasten + komen

This is very normal Dutch word order.

You could also start with another element, but then the verb still stays second:

• Morgen komen achttien gasten. = Tomorrow, eighteen guests are coming.

The singular is gast and the plural is gasten.

This is a very common Dutch plural pattern:

• singular + -en

Examples:

• gast → gasten
• boek → boeken
• tafel → tafels is a different pattern

So gasten is just the regular plural form meaning guests.

No. In this kind of sentence, achttien stays the same.

You use:

• achttien gasten
• achttien boeken
• achttien huizen

Unlike adjectives, ordinary cardinal numbers like een, twee, drie, achttien do not change form to match gender or number of the noun.

A good rough guide is akh-TEEN.

A few key points:

• The ch is the Dutch throat sound, like the ch in Scottish loch
• The stress is on -tien
• The ie sounds like ee in see

So achttien is approximately:

• akh-TEEN

The hardest part for English speakers is usually the ch sound.

A rough pronunciation guide is:

• gasten ≈ GHAS-tuh(n)
• komen ≈ KOH-muh(n)

Useful notes:

• The g in standard Dutch is usually a throaty sound, not an English g
• The a in gast is short
• The o in komen is a long o
• The final -en is often pronounced weakly in everyday speech

So the full sentence is roughly:

• akh-TEEN GHAS-tuh(n) KOH-muh(n)

Dutch present tense often covers both ideas.

So komen can correspond to:

• come
• are coming

In English, Eighteen guests are coming is usually the most natural translation in isolation. But Dutch does not need a special progressive form here.

That means Dutch present tense is often broader than English present tense.

Yes, absolutely.

Er komen achttien gasten is very common Dutch and often feels natural when you are introducing new information or saying that some people will be present.

Compare:

• Achttien gasten komen. = focuses more directly on eighteen guests
• Er komen achttien gasten. = more like There are eighteen guests coming

Both are correct. The version with er is often especially natural when mentioning a number for the first time.

For a yes/no question, Dutch usually puts the finite verb first:

• Komen achttien gasten? = Are eighteen guests coming?

That is the standard inversion pattern.

You can also ask for the number:

• Hoeveel gasten komen? = How many guests are coming?

Yes. Gast and guest are cognates, and they mean basically the same thing.

So:

• gast = guest
• gasten = guests

This is one of the easier Dutch words for an English speaker to recognize.