Learn Hardcore Indonesian: Saya mengambil kacamata pelindung yang jatuh di lantai dan mengembalikannya kepada penjaga laboratorium. - I pick up the protective goggles that fell on the floor and return them to the laboratory attendant.

Saya
- More formal and neutral.
- Safe to use in almost any situation: with strangers, in class, in writing, at work.
Aku
- Informal and more intimate.
- Used with close friends, family, or people your age in casual settings.

In this sentence, Saya makes the sentence sound neutral and slightly formal, which fits well for a context involving a laboratory and a lab attendant.

You could say Aku in a very casual story, but the tone would change to more personal/informal.

Why is the verb mengambil used instead of just ambil?

The root verb is ambil (take).

Mengambil is formed with the prefix meN-:

ambil → mengambil = to take / to pick up (active verb form)

In a full sentence with an explicit subject like Saya, Indonesian usually prefers the meN- form:

Saya mengambil kacamata = I take / took the glasses.
Ambil kacamata itu! = Take those glasses! (imperative, so the root form ambil is common here)

So mengambil is the normal active form in a descriptive sentence like this. Using just ambil with Saya would sound incomplete or like a command.

What exactly does kacamata pelindung mean, and why is pelindung placed after kacamata?

kacamata = glasses (literally: kaca = glass, mata = eye)
Together, kacamata is a single word meaning glasses or spectacles.
pelindung = protector / protective / something that protects (from lindung = protect, with prefix pe-)

kacamata pelindung literally means protective glasses, i.e. safety goggles.

In Indonesian, descriptions usually come after the noun:

kacamata pelindung = protective glasses
buku merah = red book
rumah besar = big house

So the noun kacamata comes first, then the describing word pelindung.

What is the function of yang in kacamata pelindung yang jatuh di lantai?

yang introduces a relative clause, similar to that / which / who in English.

kacamata pelindung = the protective glasses
jatuh di lantai = fell on the floor / that are on the floor (after falling)
yang jatuh di lantai = that fell on the floor / which had fallen on the floor

So:

kacamata pelindung yang jatuh di lantai
= the protective glasses that fell on the floor

yang links the noun (kacamata pelindung) to the descriptive clause (jatuh di lantai).
Without yang, the sentence would be ungrammatical or confusing here. You need yang to say the goggles that fell.

Does jatuh here mean “fell” or “falling”? There is no tense marker, so how do we know?

Indonesian verbs do not change form for tense. jatuh is simply to fall / fallen, and the time is understood from context.

In this sentence, the natural interpretation is:

kacamata pelindung yang jatuh di lantai
= the protective glasses that had fallen / that fell on the floor

We know it’s past because:

The speaker is telling a completed action:
Saya mengambil … dan mengembalikannya … = I picked them up and returned them.
You can imagine the event as:
First the goggles fell → now they are on the floor → then I picked them up and returned them.

If you needed to make time explicit, you would add a time adverb:

yang tadi jatuh di lantai = that just fell on the floor
yang sudah jatuh di lantai = that have already fallen on the floor

Why is it di lantai and not ke lantai?

di = at / in / on (location, static position)
ke = to, toward (movement to a destination)

In the sentence:

jatuh di lantai = fell, and ended up on the floor (describing where it is after falling)

If you wanted to emphasize the direction of falling to the floor at the moment it happens, you could say:

jatuh ke lantai = fell down to the floor

But in this context, di lantai is natural because we are describing the goggles that are on the floor (after falling), not focusing on the motion itself.

Can kacamata be both singular and plural? How does mengembalikannya fit if the object is “glasses”?

Yes, kacamata is usually both singular and plural:

kacamata = a pair of glasses / glasses (no separate plural form in everyday usage)

Indonesian often does not mark plural explicitly. If necessary, you can add:

sebuah kacamata = one pair of glasses (less common)
banyak kacamata = many glasses

The pronoun ending -nya in mengembalikannya can mean it or them, depending on context. So here:

mengembalikannya = returned it / them

Since kacamata is conceptually a pair, -nya naturally covers them in English, even though the Indonesian is grammatically singular/neutral.

How is mengembalikannya formed, and what exactly does it mean?

mengembalikannya is a combination of:

Root: kembali = return (go back)
Suffix: -kan → mengembalikan = to return something (cause something to go back)
Object pronoun: -nya = it / them / his / her

So:

mengembalikan = to return (an object)
mengembalikannya = to return it / them

In the sentence:

dan mengembalikannya kepada penjaga laboratorium
= and returned them to the lab attendant

The -nya refers back to the previously mentioned kacamata pelindung.

Why do we use kepada instead of ke before penjaga laboratorium?

Both ke and kepada can translate as to, but they are used differently:

ke is mainly for physical destinations or places:
- ke rumah = to the house
- ke laboratorium = to the laboratory
kepada is for recipients, usually people or entities:
- memberikan buku kepada guru = give a book to the teacher
- mengembalikannya kepada penjaga laboratorium = returned it to the lab attendant

So kepada penjaga laboratorium is correct because you are returning the object to a person (the lab attendant), not to a location.

What does penjaga laboratorium literally mean, and how is it formed?

penjaga laboratorium is a noun phrase:

jaga = to guard, watch over, look after
Prefix pe-
- jaga → penjaga = guard / caretaker / attendant (person who watches/looks after)
laboratorium = laboratory

So:

penjaga laboratorium = lab guard / lab attendant / lab caretaker

In context, it usually means the person responsible for the lab and its equipment (could be a technician, assistant, or staff member).

Could we omit yang and just say kacamata pelindung jatuh di lantai?

That would change the structure and meaning.

kacamata pelindung yang jatuh di lantai
= the protective glasses that fell on the floor (relative clause describing which glasses)

If you say:

kacamata pelindung jatuh di lantai

this reads as a full clause:
The protective glasses fell on the floor.

In your original sentence, you do not want a second full clause; you want to describe which glasses you picked up. So you need yang to form a relative clause.

Therefore, in this sentence, you cannot drop yang without changing the grammar and meaning.

Can the word order be changed, for example: Saya mengambil dan mengembalikannya kacamata pelindung yang jatuh di lantai?

No, that word order is not natural or correct in Indonesian.

The usual and clear structure is:

Verb + object:
- mengambil kacamata pelindung yang jatuh di lantai
  (take the protective glasses that fell on the floor)
Then the second verb with a pronoun object, because the object is already known:
- mengembalikannya kepada penjaga laboratorium
  (return them to the lab attendant)

You could rephrase in other natural ways, for example:

Saya mengambil kacamata pelindung yang jatuh di lantai, lalu saya mengembalikannya kepada penjaga laboratorium.

But you should not place kacamata pelindung yang jatuh di lantai after mengembalikannya; the -nya already stands for that object.

Why doesn’t Indonesian mark past tense like “I took” and “I returned”? How would you make it clearly past if needed?

Indonesian verbs do not change form for tense. mengambil can mean:

am taking
take
took

and mengembalikannya can mean:

am returning it / them
return it / them
returned it / them

Time is usually understood from context or from time words. To make it clearly past, you can add adverbs:

tadi = earlier / just now
kemarin = yesterday
tadi pagi = this morning
barusan = just now

Example:

Tadi saya mengambil kacamata pelindung yang jatuh di lantai dan mengembalikannya kepada penjaga laboratorium.
= Earlier I took the protective glasses that had fallen on the floor and returned them to the lab attendant.

Is there a difference in nuance between mengembalikannya kepada penjaga laboratorium and mengembalikan kacamata pelindung kepada penjaga laboratorium?

Yes, mainly in style and repetition:

mengembalikannya kepada penjaga laboratorium
- Uses -nya to refer back to the already mentioned kacamata pelindung.
- Avoids repeating the noun.
- Sounds smooth and natural in connected speech.
mengembalikan kacamata pelindung kepada penjaga laboratorium
- Repeats kacamata pelindung.
- Grammatically correct, but slightly heavier.
- Useful if you want to emphasize what was returned, or if it has not been clearly mentioned before.

In your original sentence, using mengembalikannya is more natural because the object has just been clearly identified.