Die polisie ondersoek die moord.

Because die is the Afrikaans definite article, meaning the.

So:

• die polisie = the police
• die moord = the murder

Unlike some languages, Afrikaans does not change the word for the based on gender or case. The same die is used very widely.

Word by word:

• Die = the
• polisie = police
• ondersoek = investigate / investigates / is investigating depending on context
• die = the
• moord = murder

So the sentence structure is very straightforward:

• subject: Die polisie
• verb: ondersoek
• object: die moord

It is a verb here.

In this sentence, ondersoek means investigates / is investigating.

Afrikaans often has words that can function as more than one part of speech depending on context. Ondersoek can also be a noun meaning investigation, but here its position after the subject shows that it is the verb.

Because Afrikaans verbs usually do not change according to the subject.

In English:

• I investigate
• she investigates

In Afrikaans, the verb normally stays the same:

• Ek ondersoek
• Sy ondersoek
• Die polisie ondersoek

This is one of the simpler features of Afrikaans grammar.

It can often mean either, depending on context.

Afrikaans simple present can cover meanings that English expresses in more than one way, including:

• The police investigate the murder
• The police are investigating the murder

Usually the surrounding context tells you which one is meant.

Grammatically, polisie is usually treated as a collective noun meaning the police as an institution or force.

So die polisie often works like English the police. It refers to the police collectively, not necessarily to one single officer.

If you want to refer to individual police officers, you would usually use a different expression, such as:

• polisiebeamptes = police officers

Because this is a normal main clause, and Afrikaans commonly uses subject–verb–object order in simple statements.

So:

• Die polisie = subject
• ondersoek = verb
• die moord = object

That gives:

• Die polisie ondersoek die moord

This is very close to English:

• The police investigate the murder

Yes. In a simple statement, the verb is in the second position, and with a basic subject-first sentence that gives you:

• Die polisie ondersoek die moord.

But if you move another element to the front, Afrikaans keeps the verb in second position:

• Vandag ondersoek die polisie die moord.
  Today the police are investigating the murder.

That is an important Afrikaans pattern to get used to.

Yes. Moord is closely related in meaning to murder.

This is a helpful vocabulary point because Afrikaans and English share many words that are historically related or easy to recognize.

A rough English-friendly guide is:

• ondersoek ≈ ON-duhr-sook

A few notes:

• onder sounds a bit like under, but not exactly
• soek rhymes roughly with book only in a very loose way; the vowel is not exactly the same as English

A more important beginner goal than perfect accent is recognizing that it is one word meaning investigate.

No. Afrikaans does not use grammatical gender the way languages like German do.

So you do not need to learn separate words for the based on masculine, feminine, or neuter nouns. That is why die can be used for both polisie and moord here.

Afrikaans typically uses a double negative with nie ... nie.

So:

• Die polisie ondersoek nie die moord nie.

That means:

• The police are not investigating the murder.

This double nie pattern is a very common feature of Afrikaans.

Common ways are:

• Die polisie het die moord ondersoek.
  The police investigated the murder.

• Die polisie sal die moord ondersoek.
  The police will investigate the murder.

Notice that with het in the past tense, the main verb moves toward the end:

• het ... ondersoek

That is a very common Afrikaans pattern.