Tjue personer kom.

Because personer is the indefinite plural form of person.

A quick overview:

• en person = one person
• personen = the person
• personer = people / persons
• personene = the people

Since tjue refers to more than one person, Norwegian uses the plural: personer.

After a number, Norwegian normally uses the indefinite plural noun with no article:

• to personer
• fem biler
• tjue personer

So tjue personer is the normal pattern. You do not add something like English the unless you specifically mean a definite group. For example:

• Tjue personer kom. = an indefinite group of twenty people
• De tjue personene kom. = the twenty people came

Yes. Kom is the past tense of komme.

Useful forms are:

• komme = to come
• kommer = come / am coming / are coming
• kom = came
• har kommet = have/has come

So in this sentence, kom shows that the action happened in the past.

No. In Norwegian, verbs do not change for person or number the way they do in English.

For example:

• Jeg kommer = I come / I am coming
• Du kommer = you come
• Han kommer = he comes
• Vi kommer = we come
• De kommer = they come

The verb form stays the same. So kom would be used whether it was one person or many:

• En person kom.
• Tjue personer kom.

Tjue personer kom is the normal word order for a statement: subject + verb.

• Tjue personer = the subject
• kom = the verb

If you say Kom tjue personer?, that would normally sound like a yes/no question: Did twenty people come?

Norwegian main clauses follow the V2 rule, which means the finite verb is usually in the second position. In this sentence, the whole subject phrase Tjue personer counts as the first element, so kom comes second.

You would normally say:

De tjue personene kom.

Here is what changes:

• de = the
• tjue = twenty
• personene = the people

So:

• Tjue personer kom. = twenty people came
• De tjue personene kom. = the twenty people came

That definite version refers to a specific group already known in the context.

Yes, often you can, but the nuance is a little different.

• personer is a neutral, common word when counting people.
• mennesker means human beings / people and can sound a bit broader or more general.

So Tjue mennesker kom is possible, but Tjue personer kom is very natural when you are simply stating how many people came.

Yes, you can. The grammar is the same.

Both are possible:

• Tjue personer kom.
• 20 personer kom.

Writing the number as a word can look a bit more formal or natural in running text, while digits are also very common, especially in practical or factual writing.

In standard Norwegian, tjue is often pronounced roughly like shoo-eh, but the exact sound varies by dialect.

A few helpful points:

• the tj sound is not pronounced like English t + y in careful Norwegian speech
• the word has two syllables
• many speakers say it quite smoothly and quickly in everyday speech

Pronunciation varies a lot across Norway, so do not worry if you hear different versions. The spelling tjue stays the same in standard Bokmål.

Yes, but only if the context already makes it clear that you mean people.

For example, if you are already talking about guests or students, Tjue kom can mean Twenty came.

But without context, Tjue personer kom is clearer, because it tells the listener exactly what tjue refers to.