Antrean di loket pendaftaran bergerak pelan-pelan.

Antrean means a queue / a line of people waiting. In this sentence, it is the subject.

So:

• Antrean = the line / the queue
• bergerak = moves
• pelan-pelan = slowly

A natural English translation is The queue at the registration counter is moving slowly.

A useful note: in standard Indonesian, antrean is preferred over antrian, although many people do say antrian in everyday speech.

di is a preposition of location, usually meaning at, in, or on, depending on context.

So:

• di loket pendaftaran = at the registration counter

Here it tells you where the queue is.

Be careful not to confuse:

• di
  • place = preposition, written separately
    
    • di loket = at the counter
• di-
  • verb = passive prefix, written together
    
    • dibuka = opened

So in this sentence, di is definitely the location word at.

It is a noun phrase:

• loket = counter, booth, service window
• pendaftaran = registration

Together:

• loket pendaftaran = registration counter / registration desk / registration window

The exact English translation depends on the setting:

• in a hospital: registration desk
• in an office or station: registration counter
• at a ticket-style window: registration window

Because in Indonesian, bergerak literally means to move, but it can also be used naturally for things like:

• a line moving forward
• traffic moving
• an elevator moving
• a crowd shifting

So in this sentence, antrean bergerak means the queue is advancing or moving along, not that the queue is dancing around or moving randomly.

Examples:

• Lalu lintas bergerak pelan. = Traffic is moving slowly.
• Antrean mulai bergerak. = The line started moving.

Pelan-pelan is a reduplicated form of pelan.

• pelan = slow, softly, gently
• pelan-pelan = slowly, gently, bit by bit

In many cases, reduplication makes the expression sound more natural, softer, or more adverbial.

So:

• bergerak pelan = moves slowly
• bergerak pelan-pelan = moves slowly / inching along / moving little by little

In this sentence, pelan-pelan suggests the queue is moving in a gradual, slow way.

Yes. These are also very common.

Compare:

• pelan-pelan = slowly, gently, little by little
• perlahan = slowly
• perlahan-lahan = slowly, gradually

So these are all possible:

• Antrean di loket pendaftaran bergerak pelan-pelan.
• Antrean di loket pendaftaran bergerak perlahan.
• Antrean di loket pendaftaran bergerak perlahan-lahan.

They are very similar in meaning.
Pelan-pelan often sounds a bit more conversational.
Perlahan can sound a bit more neutral or formal.

Indonesian often does not use a verb like English is/are in the same way.

In this sentence, the main verb is already bergerak = move. So Indonesian simply says:

• Antrean ... bergerak pelan-pelan
• literally: The queue ... moves slowly

There is no need for a separate word meaning is.

More generally, Indonesian often leaves out a copula in sentences like:

• Dia guru. = He is a teacher.
• Tempat itu ramai. = That place is crowded.

Indonesian verbs usually do not change form for tense. Time is often understood from:

• context
• time words
• the situation

So bergerak by itself can mean:

• moves
• is moving
• was moving

depending on context.

In this sentence, without extra context, English usually translates it as:

• The queue at the registration counter is moving slowly or
• The queue at the registration counter moves slowly

If you want to make the ongoing sense clearer in Indonesian, you could say:

• Antrean di loket pendaftaran sedang bergerak pelan-pelan.

Here sedang emphasizes that the action is in progress: is moving.

The sentence follows a very common Indonesian pattern:

• Subject
  • location phrase
    • verb
      • adverb

So here:

• Antrean = subject
• di loket pendaftaran = location
• bergerak = verb
• pelan-pelan = adverb

This order is natural and clear.

You could also say:

• Antrean bergerak pelan-pelan di loket pendaftaran.

But that can sound slightly less natural in some contexts, because di loket pendaftaran is closely tied to antrean: it is the queue at that place.

So the original sentence is a very normal way to package the information.

It can be understood as doing both, but most naturally it tells you which queue we are talking about:

• the queue at the registration counter

At the same time, it also gives the location where the moving is happening.

So structurally, Indonesian allows this kind of flexible phrase placement. In practice, a learner will usually understand it as:

• [Antrean di loket pendaftaran] = the queue at the registration counter
  then
• bergerak pelan-pelan = is moving slowly

It usually refers to the queue/line as a whole, which of course is made up of people.

So it is not focusing on individual people, but on the line as a unit.

For example:

• Antreannya panjang. = The queue is long.
• Antrean bergerak cepat. = The queue is moving fast.

If you want to focus on the people, you might say something like:

• Orang-orang yang mengantre = the people waiting in line

They come from the same root idea, but they have different roles:

• antrean = a noun, queue / line
• mengantre = a verb, to queue / to stand in line

Examples:

• Antrean di loket pendaftaran panjang. = The queue at the registration counter is long.
• Mereka mengantre di loket pendaftaran. = They are queuing at the registration counter.

So in your sentence, antrean is the thing that is moving.

It is very common and useful. It can mean:

• slowly
• gently
• take it easy
• little by little

Examples:

• Jalan pelan-pelan. = Walk slowly.
• Buka pintunya pelan-pelan. = Open the door gently.
• Pelan-pelan saja. = Just take it slow / No rush.
• Saya belajar pelan-pelan. = I’m learning little by little.

So in your sentence, bergerak pelan-pelan gives the sense that the queue is advancing slowly and gradually.