Zestien mensen werken hier.

Mensen is the correct plural of mens (person / human being). It is an irregular plural, so you just have to learn it as a set:

• de mens = the person / the human
• de mensen = the people

This is very common in Dutch. In this sentence, zestien mensen simply means sixteen people.

After a number, Dutch usually uses the noun directly, just like English:

• zestien mensen = sixteen people
• drie boeken = three books
• twee huizen = two houses

So you do not say de zestien mensen unless you specifically mean the sixteen people.

Because the subject is plural: zestien mensen.

In the present tense, werken behaves like this:

• ik werk = I work
• jij werkt = you work
• hij/zij werkt = he/she works
• wij werken = we work
• jullie werken = you all work
• zij werken = they work

Since zestien mensen is plural, Dutch uses the plural form werken.

Yes. Zestien means sixteen.

Here it works very much like English:

• zestien mensen = sixteen people

A useful thing to know is that Dutch numbers are often written as one word, especially lower numbers like this. So zestien is one single word.

This is the normal word order for a simple Dutch main clause:

subject + finite verb + other information

So:

• Zestien mensen = subject
• werken = finite verb
• hier = adverb of place

Dutch main clauses follow the verb-second rule, often called V2. In this sentence, the subject comes first, so the verb comes second.

Yes. Dutch often moves place words to the front for emphasis or style:

• Hier werken zestien mensen.

That is also correct. Because Dutch is a verb-second language, if hier comes first, the verb werken still has to come second, and the subject moves after the verb.

So:

• Zestien mensen werken hier.
• Hier werken zestien mensen.

Both are correct.

Hier means here.

It often comes later in the sentence, as in:

• Zestien mensen werken hier.

But it can also come first:

• Hier werken zestien mensen.

Both are natural. Dutch is fairly flexible with adverbs like hier, but the verb-second rule still matters in main clauses.

Yes. After numbers greater than one, Dutch uses the plural noun:

• één mens = one person
• twee mensen = two people
• zestien mensen = sixteen people

So zestien mens would be incorrect.

A rough English-style guide is:

• zestien ≈ zes-TEEN
• mensen ≈ MEN-suh
• werken ≈ VER-kuh or WER-kuh depending on accent
• hier ≈ heer

A few notes:

• The Dutch w is not exactly like English w; it is often closer to a soft v sound.
• The r in werken depends on accent and can sound different in different regions.
• hier is one syllable in normal speech.

Not exactly, though they can overlap.

• mensen = people, humans; the normal everyday word
• personen = persons; more formal, official, or administrative

In an ordinary sentence like this, mensen is the natural choice:

• Zestien mensen werken hier.

Using personen here would sound more formal or bureaucratic.

Yes. Er werken hier zestien mensen is also a very natural Dutch sentence.

This kind of er is often used when introducing the existence or presence of something, similar to English there in There are sixteen people working here.

So these are all possible, with slightly different emphasis:

• Zestien mensen werken hier.
• Hier werken zestien mensen.
• Er werken hier zestien mensen.

The basic meaning stays the same, but the focus shifts a little.