Wir fragen den Polizisten.

Because wir takes the -en verb ending in the present tense.

The verb is fragen = to ask.

Present tense:

• ich frage
• du fragst
• er/sie/es fragt
• wir fragen
• ihr fragt
• sie/Sie fragen

So wir fragen means we ask.

That is normal for many German verbs. The wir form and the sie/Sie form are often identical to the infinitive.

So:

• infinitive: fragen
• wir form: wir fragen
• sie form: sie fragen
• Sie form: Sie fragen

You have to use the subject to tell which one it is.

Because Polizisten is the direct object of the verb fragen, and direct objects take the accusative case in German.

• nominative: der Polizist = the policeman
• accusative: den Polizisten = the policeman (as the object)

In this sentence:

• Wir = subject
• fragen = verb
• den Polizisten = direct object

So German uses the accusative form: den Polizisten.

Because Polizist is a type of masculine noun called a weak noun or n-noun.

These nouns add -en (or sometimes -n) in almost all forms except the nominative singular.

So:

• nominative singular: der Polizist
• accusative singular: den Polizisten
• dative singular: dem Polizisten
• genitive singular: des Polizisten

This pattern is very common with nouns referring to people, especially professions or nationalities, such as:

• der Student → den Studenten
• der Kollege → den Kollegen
• der Junge → den Jungen

In this sentence, it is singular because fragen takes an accusative object, and den Polizisten is the masculine singular accusative form.

If it were plural in the accusative, it would be:

• die Polizisten

So:

• Wir fragen den Polizisten. = We ask the policeman.
• Wir fragen die Polizisten. = We ask the policemen.

Very often, yes, when you mean ask someone.

German says:

• jemanden fragen = to ask someone

So:

• Ich frage den Lehrer.
• Wir fragen den Polizisten.

This is different from some other German verbs that require a preposition.

Also compare:

• jemanden fragen = ask someone
• nach etwas fragen = ask for something / ask about something

For example:

• Wir fragen den Polizisten. = We ask the policeman.
• Wir fragen nach dem Bahnhof. = We ask about / for the train station.

Yes, German word order is flexible, but the verb still stays in second position in a normal main clause.

The neutral order is:

• Wir fragen den Polizisten.

You could also say:

• Den Polizisten fragen wir.

That puts extra emphasis on den Polizisten. It might sound like It’s the policeman that we’re asking.

So the original sentence is the most neutral and basic version.

Normally, no. In a full statement, German usually needs the subject to be stated unless it is understood from context in very informal speech.

So the normal sentence is:

• Wir fragen den Polizisten.

Without wir, it would not sound like a complete standard sentence.

Yes. It is pronounced roughly like po-li-TSIS-ten.

A simple English-friendly approximation is:

• poh-lee-TSIS-ten

The stress is on the -zis- syllable:

• Po-li-ZIS-ten

Yes, it is a perfectly normal sentence grammatically. On its own, it means We ask the policeman or We are asking the policeman, depending on context.

In real conversation, people might also say:

• Wir fragen mal den Polizisten. = Let’s ask the policeman.
• Fragen wir den Polizisten. = Let’s ask the policeman.

But Wir fragen den Polizisten. is a completely natural basic sentence for learning the structure.

It follows the standard German main-clause pattern:

subject + verb + object

So:

• Wir = subject
• fragen = verb
• den Polizisten = object

This is one of the most useful basic sentence patterns in German.