Learn Hardcore Indonesian: Dia memperbaiki motor di rumah. - He/She fixes the motorcycle at home.

Indonesian dia is gender‑neutral and can mean he, she, or even they (singular, when context makes that clear).
You find out which one is meant only from context, for example:

Dia memperbaiki motor di rumah. – If you were already talking about a man, it means He is repairing the motorcycle at home.
The same sentence in a conversation about a woman means She is repairing the motorcycle at home.

There is no gender marking in the pronoun itself.

How do I know if this sentence is in the past, present, or future?

Indonesian verbs usually do not change form for tense.
Dia memperbaiki motor di rumah can mean:

He/She repaired the motorcycle at home. (past)
He/She is repairing the motorcycle at home. (present)
He/She repairs the motorcycle at home. (habitual)

The tense is understood from context or from time words:

Kemarin dia memperbaiki motor di rumah. – Yesterday he/she repaired…
Sekarang dia memperbaiki motor di rumah. – Now he/she is repairing…
Besok dia akan memperbaiki motor di rumah. – Tomorrow he/she will repair…

What is the difference between Dia memperbaiki motor di rumah and Dia sedang memperbaiki motor di rumah?

Sedang is an aspect marker that emphasizes an ongoing action, similar to English -ing:

Dia memperbaiki motor di rumah.
– He/She repairs / is repairing the motorcycle at home. (neutral; can be present, past, or habitual)
Dia sedang memperbaiki motor di rumah.
– He/She is in the middle of repairing the motorcycle at home (right now).

So sedang makes it clear that the action is happening at this moment.

Does motor mean motorcycle, car, or just engine?

In everyday Indonesian:

motor almost always means motorcycle (a motorbike / scooter).
mobil means car.
mesin means machine or engine.

So Dia memperbaiki motor di rumah is naturally understood as:

He/She is repairing the motorcycle at home.

If you want to be more explicit or formal, you can say sepeda motor (literally “motor bicycle”) for motorcycle.

Why do we need di in di rumah? Can I just say Dia memperbaiki motor rumah?

You must use the preposition di to mark location:

di = at / in / on
rumah = house / home

So:

Dia memperbaiki motor di rumah. – He/She repairs the motorcycle at home.

If you say Dia memperbaiki motor rumah, it sounds wrong; without di, rumah looks like a noun modifying another noun (like house motor), not a place where the action happens. Indonesian needs di before location nouns in this kind of sentence.

What is the difference between di rumah and ke rumah?

di rumah = at home / in the house (location, where something is)
ke rumah = to (the) house / to home (direction, where something is going)

Examples:

Dia memperbaiki motor di rumah.
– He/She repairs the motorcycle at home. (location)
Dia pergi ke rumah.
– He/She goes to the house / goes home. (movement toward that place)

You wouldn’t say memperbaiki motor ke rumah; for repairing, you need a location, so di is correct.

Can I change the word order, like Di rumah dia memperbaiki motor?

Yes, Indonesian word order is flexible as long as you keep the basic logical structure. These are all natural:

Dia memperbaiki motor di rumah.
– neutral order; very common.
Di rumah, dia memperbaiki motor.
– starts with the place; emphasizes at home.
Dia di rumah memperbaiki motor.
– also possible, but sounds a bit more like spoken style and can put emphasis on di rumah.

All three mean roughly the same thing; the differences are mostly in emphasis, not grammar.

How do I say his motorcycle or her motorcycle in this sentence?

Indonesian often uses -nya to show possession or definiteness:

Dia memperbaiki motornya di rumah.
Literally: He/She repairs the motorcycle-ny a at home.

Depending on context, motornya can mean:

his motorcycle
her motorcycle
the motorcycle (a specific one we already know about)

There is no separate form to distinguish his vs her; context tells you which is meant.

Can I drop dia and just say Memperbaiki motor di rumah?

Yes, in casual conversation pronouns are often dropped when the subject is obvious from context.

Memperbaiki motor di rumah.
– (He/She/I/They) repair the motorcycle at home.

But:

In written Indonesian or when you first introduce the information, it is more natural to include dia.
Without dia, the sentence feels more like a fragment or a note (e.g., on a schedule or in a message: “Repairing the motor at home”).

So grammatically it can be omitted, but including dia is clearer.

What is the structure of the verb memperbaiki? Why does it look so long?

Memperbaiki is a derived verb:

Root adjective: baik = good
With affixes: mem-per-baik-i → memperbaiki

Rough meaning: to make good, to fix, to improve, to repair.

So Dia memperbaiki motor di rumah literally feels like:
“He/She is making the motorcycle good (again) at home.”

The affixes mem-, per-, and -i together create a verb that means to repair / to improve.

Is memperbaiki formal? What would people say in casual speech?

Memperbaiki is neutral and fine in both written and spoken Indonesian, but it sounds a bit standard / formal.

In everyday informal speech, people often use:

benerin (from benar = correct), especially in Jakarta / colloquial Indonesian.

For example:

Dia lagi benerin motor di rumah.
– He/She is fixing the motorcycle at home.

So:

memperbaiki – neutral/standard, suitable for writing and polite speech
benerin – colloquial, informal conversation, especially in big cities