Learn Hardcore Malay: Di dapur, saya mencuci periuk dan pinggan mangkuk dengan sabun pinggan yang wangi. - In the kitchen, I wash the pot and the plates and bowls with fragrant dish soap.

makes the location the topic or focus first (kind of like saying “In the kitchen, I wash…” in English),
sounds very natural in storytelling or description.

Putting di dapur at the end is also very common and maybe feels more like neutral word order:

Saya mencuci periuk dan pinggan mangkuk di dapur.

So this is mostly about emphasis and style, not grammar rules.

What is the role of di in di dapur? Is it a preposition or a prefix?

In di dapur, di is a preposition meaning “at / in / on” (location).

Malay also has di- as a prefix that forms the passive voice (e.g. ditulis, dibaca), but that is different:

di dapur → di (preposition) + dapur (noun: kitchen)
dibasuh → di- (passive prefix) + basuh (verb: to wash)

You can often tell them apart because:

Prepositional di is written separately: di rumah, di sekolah, di dapur
Passive di- is written attached to the verb: ditulis, dimasak, dibasuh

Is the comma after di dapur necessary?

In everyday writing, the comma is optional here. It is mainly used to:

show a pause after the introductory phrase (Di dapur, ...),
make the sentence easier to read.

Both are acceptable:

Di dapur, saya mencuci periuk dan pinggan mangkuk...
Di dapur saya mencuci periuk dan pinggan mangkuk...

In more formal writing, you will often see the comma, but leaving it out is not considered wrong in normal prose.

What is the difference between mencuci and membasuh / basuh?

All of these are related to washing, but there are some tendencies in usage.

cuci / mencuci
- Often used for washing things to make them clean or free from dirt/germs.
- Common with: pinggan, baju, tangan, muka, kereta.
- mencuci is the formal/affixed form; cuci is more casual.
basuh / membasuh
- Also means to wash, very widely used.
- In everyday speech many people say basuh for dishes, clothes, etc.
- membasuh is more formal; basuh is everyday speech.

In your sentence, you could also say:

Saya basuh periuk dan pinggan mangkuk...
Saya membasuh periuk dan pinggan mangkuk...

All are understandable. Mencuci may sound slightly more formal or “textbook”, but it is perfectly natural.

What exactly does periuk mean? Is it any kind of pot or something specific?

Periuk is a cooking pot, typically a deep pot used on the stove to boil or cook things like rice, soup, or curry.

Some related words:

periuk – pot
kuali – frying pan / wok
periuk nasi – rice cooker (literally: rice pot)
periuk tekanan – pressure cooker

So in this sentence, periuk means the cooking pots you used to prepare food.

Why is it pinggan mangkuk and not just pinggan or pinggan dan mangkuk?

Pinggan mangkuk is a common fixed pair (a kind of set phrase):

pinggan – plates
mangkuk – bowls
pinggan mangkuk – “dishes / tableware” (plates and bowls together)

You can think of pinggan mangkuk as a single idea: all the dishes.

You could say:

pinggan dan mangkuk – more literal: “plates and bowls”
pinggan – sometimes used loosely to mean “dishes” too, depending on context

But pinggan mangkuk is very natural when you mean all eating dishes that need washing.

Is pinggan mangkuk singular or plural? Why no plural marker?

Malay usually does not mark plural with an ending like English -s.

pinggan can mean plate or plates.
pinggan mangkuk can mean plate(s) and bowl(s).

Number is understood from context:

saya ada satu pinggan – I have one plate.
saya mencuci pinggan mangkuk – I wash the dishes (obviously more than one).

You can mark plurality explicitly in some ways (e.g. banyak pinggan, semua pinggan), but it is not required.

How does dengan work in this sentence? Is it “with” or “using”?

In this sentence, dengan means “with / using”:

... mencuci periuk dan pinggan mangkuk dengan sabun pinggan ...
→ wash the pots and dishes with / using dish soap

Common functions of dengan include:

with (together with someone) – Saya pergi dengan kawan.
with (using a tool or means) – Tulis dengan pensel.
in (a manner or way) – Dia bercakap dengan perlahan.

Here it clearly marks the tool/means used to wash: sabun pinggan.

What does sabun pinggan literally mean, and is this how you normally say “dish soap”?

Literally:

sabun – soap
pinggan – plate(s)

In Malay, a common way to show “X for Y” is noun + noun:

sabun pinggan – soap (for) dishes → dish soap
ubat gigi – medicine (for) teeth → toothpaste
minyak rambut – oil (for) hair → hair oil

So sabun pinggan is a natural, everyday way to say dish soap.
You may also see:

sabun basuh pinggan
cecair pencuci pinggan

These are longer or more formal, but sabun pinggan is short and common.

What is the function of yang in sabun pinggan yang wangi?

Yang introduces a relative clause or descriptive phrase.

sabun pinggan – dish soap
yang wangi – that is fragrant / which is fragrant

So:

sabun pinggan yang wangi
literally: the dish soap that is fragrant

Structure:

noun (sabun pinggan)
- yang
  - description (wangi)

This pattern is very common in Malay:

baju yang cantik – the shirt that is beautiful
rumah yang besar – the house that is big
orang yang baik – the person who is kind

Why is wangi at the end? Could it come before sabun pinggan?

In Malay, adjectives and descriptive phrases usually come after the noun:

Malay: sabun pinggan yang wangi
English: fragrant dish soap

You cannot say wangi sabun pinggan in the same way English puts the adjective first.
The typical patterns are:

noun + adjective – baju merah (red shirt)
noun + yang + adjective – baju yang merah (the shirt that is red)

So wangi must follow sabun pinggan (yang).

How is tense expressed here? How do we know if it means “I wash”, “I am washing”, or “I washed”?

Malay verbs usually do not change form for tense. The verb mencuci itself is tenseless.

The sentence:

Saya mencuci periuk dan pinggan mangkuk...

can mean:

I wash the pots and dishes...
I am washing the pots and dishes...
I washed the pots and dishes...

The exact time is understood from context or from time words like:

tadi (earlier / just now) – Tadi, saya mencuci periuk...
semalam (yesterday) – Semalam, saya mencuci periuk...
sekarang (now) – Sekarang saya mencuci periuk...
selalu (always) – Saya selalu mencuci periuk...

Without such words, the English translation can be any natural tense that fits the context.

Why use saya here? Could we use aku instead?

Both saya and aku mean “I / me”, but they differ in formality and context:

saya
- polite, neutral
- used with strangers, in formal situations, at work, in writing
- safe default pronoun for learners
aku
- casual, intimate
- used with close friends, family, or in songs, poetry
- can sound too informal or even rude in the wrong context

In your sentence:

Di dapur, saya mencuci periuk... – polite/neutral
Di dapur, aku mencuci periuk... – casual, intimate tone

For textbooks and general teaching, saya is preferred.

Could we drop saya and just say Di dapur, mencuci periuk dan pinggan mangkuk...?

In most cases, you should keep the subject pronoun, especially in simple sentences like this.

Di dapur, saya mencuci periuk... – clear: I wash the pots
Di dapur, mencuci periuk... – sounds incomplete or like part of a longer sentence

Malay can sometimes drop pronouns when context is extremely clear (especially in conversation), but for learners and in standard written sentences, it is better to include saya to avoid ambiguity.