De polishouder controleert het polisnummer.

Because Dutch forms compounds by writing the parts together as one word much more often than English does.

• polis
  • houder → polishouder
• polis
  • nummer → polisnummer

This is very normal in Dutch. English often uses two words, or sometimes a hyphen, where Dutch prefers one compound word.

A useful rule:

• in Dutch, the last part of the compound is the main noun
• the earlier part(s) give extra information

So:

• polishouder = a kind of houder
• polisnummer = a kind of nummer

Dutch nouns have grammatical gender, and that affects the article:

• de for common-gender nouns
• het for neuter nouns

Here:

• houder is a de-word, so polishouder is also a de-word
• nummer is a het-word, so polisnummer is also a het-word

With compounds, the article is usually determined by the last part of the word.

So:

• de polishouder
• het polisnummer

This is an important pattern in Dutch compounds.

Because the subject is de polishouder, which is third person singular: he/she/it.

In the present tense, Dutch verbs usually take -t with:

• jij/u
• hij/zij/het
• singular noun subjects like de polishouder

The infinitive is controleren.
Its stem is controleer.
Then for third person singular:

• ik controleer
• de polishouder controleert

So the -t is just the normal present-tense ending here.

No, this is the basic Dutch main-clause order:

Subject + finite verb + object

So:

• De polishouder = subject
• controleert = finite verb
• het polisnummer = object

This is very similar to normal English word order in a simple statement.

However, Dutch has the verb-second rule in main clauses. That means the finite verb must stay in the second position.

For example:

• De polishouder controleert het polisnummer.
• Vandaag controleert de polishouder het polisnummer.

In both sentences, the verb controleert is in second position.

Because Dutch simple present often covers both:

• checks
• is checking

So De polishouder controleert het polisnummer can mean:

• the policyholder checks the policy number
• the policyholder is checking the policy number

Dutch does have ways to emphasize an ongoing action, such as is het polisnummer aan het controleren, but in ordinary sentences the simple present is very common.

Not usually. This is a very useful vocabulary point.

In Dutch, controleren usually means:

• to check
• to inspect
• to verify

So in this sentence it means the policyholder is checking the policy number.

English to control often means to direct, to manage, or to have power over, and that is usually not what Dutch controleren means.

So this is a classic false friend to watch out for.

The object here is het polisnummer.

You can identify it because:

• de polishouder is the person doing the action
• controleert is the action
• het polisnummer is the thing being checked

So:

• subject = de polishouder
• verb = controleert
• direct object = het polisnummer

A simple English-style question can help:

• Who checks? → de polishouder
• What does the policyholder check? → het polisnummer

Because Dutch does not capitalize all nouns.

Only the first word of the sentence and proper names are capitalized, just as in English.

So:

• De polishouder controleert het polisnummer.

But inside a sentence, common nouns stay lowercase:

• de polishouder
• het polisnummer

This is different from German, where all nouns are capitalized.

In Dutch compounds, the main stress is often on the first part of the compound.

So you would usually hear something like:

• PO-lishouder
• PO-lisnummer

The exact pronunciation may vary slightly by speaker, but as a learner, stressing the first element is a good general rule for many Dutch compounds.

The most likely plural forms are:

• de polishouder → de polishouders
• het polisnummer → de polisnummers

Notice two things:

1. The plural article is always de

   • de polishouders
   • de polisnummers

2. The compound stays together in the plural too

   • not separate words
   • just add the plural ending to the whole compound

So you might get:

• De polishouders controleren de polisnummers.