Vissa människor vandrar snabbt.

Vissa means some or certain. It often points to a particular group within a larger whole, so it can feel a bit like certain people.

Compared with några:

• vissa människor = some/certain people
• några människor = some people, often more about an unspecified number

So vissa can sound slightly more selective or contrastive, as in some people do this, others do not.

Also, vissa is the plural form of viss, so it matches the plural noun människor.

In Swedish, plural indefinite nouns usually do not take an article like English some or a/an.

So Swedish says:

• människor = people
• vissa människor = some/certain people

Here, vissa already functions as a determiner, so no extra article is needed.

The singular is en människa.

The main forms are:

• en människa = a person / a human
• människor = people / humans
• människan = the person / the human
• människorna = the people / the humans

So in this sentence, människor is simply the indefinite plural form.

Not exactly.

Vandra often means:

• to hike
• to wander
• to walk, especially in a more descriptive or extended sense

By contrast, gå is the more general everyday verb for to go or to walk.

So:

• De går snabbt = They walk quickly
• De vandrar snabbt = They hike/wander/walk quickly

In many contexts, vandra sounds more literary, outdoorsy, or less everyday than gå.

Because vandrar is the present tense of vandra.

A very common Swedish pattern is:

• infinitive: vandra
• present: vandrar
• past: vandrade
• supine: vandrat

Unlike English, Swedish verbs do not change for person:

• jag vandrar
• du vandrar
• han/hon vandrar
• vi vandrar

So -r here marks the present tense, not agreement with människor.

Because snabbt is being used as an adverb here.

• snabb = quick, fast as an adjective
• snabbt = quickly, fast as an adverb

In this sentence, snabbt describes the verb vandrar, so Swedish uses the adverb form.

Compare:

• en snabb människa = a fast person
• De vandrar snabbt = They walk/hike quickly

A useful rule is that many Swedish adverbs are formed with the -t form of the adjective.

The word order is:

Vissa människor + vandrar + snabbt
subject + verb + adverb

That is very normal Swedish main-clause word order.

Swedish is a verb-second language, which means the finite verb usually comes in the second position in a main clause. Here, the subject phrase Vissa människor is in first position, so the verb vandrar comes second.

That is why Vissa människor snabbt vandrar sounds wrong in ordinary Swedish.

Yes. That is often a very good translation.

Depending on context, vissa människor can mean:

• some people
• certain people

If the sentence is making a general observation, some people is usually the most natural English translation. If you want to emphasize a particular subgroup, certain people can fit better.

A simple approximate pronunciation is:

VIS-sa MEN-ni-skor VAN-drar snabbt

A few notes:

• vissa: the first syllable is stressed
• ä in människor sounds somewhat like the e in bed
• människor is roughly MEN-ni-skor
• vandrar is roughly VAN-drar
• snabbt is often pronounced close to snapt in normal speech

So the whole sentence is approximately:

VIS-sa MEN-ni-skor VAN-drar snapt