Learn Hardcore Indonesian: Pencahayaan di ruang tamu itu nyaman untuk membaca. - The lighting in that living room is comfortable for reading.

cahaya = light (the light itself, as a physical thing)
- e.g. cahaya matahari = sunlight
pencahayaan = lighting or illumination (the overall lighting condition or arrangement)
- e.g. pencahayaan di ruangan ini buruk = the lighting in this room is bad
lampu = lamp / light bulb / light fixture (the object that produces light)
- e.g. nyalakan lampunya = turn on the lamp

In the sentence Pencahayaan di ruang tamu itu nyaman untuk membaca, pencahayaan is about the general lighting conditions in the living room, not a specific lamp.

What is the role of itu in ruang tamu itu? Does it mean that or the?

Itu is a demonstrative that literally means that, but in Indonesian it often works like the when you are talking about something specific and already known in the context.

ruang tamu = a living room / living rooms (general)
ruang tamu itu = that living room / the living room (the specific one we both know)

So di ruang tamu itu = in that/the living room (we’re talking about).

If you drop itu:

Pencahayaan di ruang tamu nyaman untuk membaca.
This sounds more general: Lighting in (a) living room is comfortable for reading (like a general statement or description).

With itu, it clearly refers to a specific living room.

Where is the verb “to be” (is) in this sentence? Why is it missing?

Indonesian normally omits “to be” (like is/are) when linking a subject to an adjective or a noun in the present tense.

English: The lighting … is comfortable for reading.
Indonesian: Pencahayaan di ruang tamu itu nyaman untuk membaca.

There is no word that directly corresponds to “is” here. The structure is simply:

Pencahayaan di ruang tamu itu (subject)
nyaman untuk membaca (predicate)

You can use adalah as a kind of “is”, but it’s usually used before a noun or noun phrase, not an adjective like nyaman. Saying:

Pencahayaan di ruang tamu itu adalah nyaman untuk membaca.

is not natural; it sounds wrong or extremely awkward.

How is pencahayaan formed from cahaya? What do peN- and -an do?

Pencahayaan comes from the root cahaya (light) with the circumfix peN- … -an:

cahaya → peN- + cahaya + -an → pencahayaan

The circumfix peN- … -an often turns a base into a noun that refers to:

a process
a result
or a general concept related to the base word

So:

cahaya = light
pencahayaan = lighting / illumination (the state or arrangement of light)

Some other examples:

ajar → pengajaran = teaching, instruction
baca → pembacaan = reading (as an act, e.g., reading of a text)

Why is it ruang tamu and not ruangan tamu? What’s the difference between ruang and ruangan?

ruang = room / space (basic root)
ruangan = room / enclosed space, often more concrete and specific

However, certain combinations are fixed expressions, and ruang tamu is one of them:

ruang tamu = living room (standard phrase)

Saying ruangan tamu would sound odd in this meaning; people almost always say ruang tamu when they mean living room.

Why is it nyaman untuk membaca and not something like baik untuk membaca or enak untuk membaca?

All three can work, but they have slightly different nuances:

nyaman untuk membaca
- nyaman = comfortable
- Focuses on comfort (lighting that makes you feel at ease while reading).
baik untuk membaca
- baik = good
- More neutral/functional: the lighting is good/suitable for reading (not necessarily about comfort).
enak untuk membaca
- enak = literally “tasty”, but colloquially also “pleasant / nice / comfy”
- Informal and casual; nyaman sounds more neutral/formal, enak more relaxed and spoken.

In the given sentence, nyaman fits well because we’re talking about the comfort of the lighting for reading.

What does untuk do in nyaman untuk membaca? Is it like for + -ing in English?

Yes. Untuk roughly corresponds to for (for the purpose of).

untuk + verb ≈ for (the purpose of) doing [verb]

So:

nyaman untuk membaca = comfortable for reading / comfortable to read (in)

More examples:

Baik untuk kesehatan. = Good for health.
Tempat ini bagus untuk belajar. = This place is good for studying.

Why is it membaca and not just baca after untuk?

Both are possible, but they differ in register (formality) and nuance:

untuk membaca
- more standard and formal
- fits well in written language or careful speech
untuk baca
- more informal / conversational
- common in everyday speech

Grammatically, meN- (here me- → membaca) marks an active verb:

baca = root “read”
membaca = “to read” (active verb form)

In textbooks and formal writing, you will almost always see untuk + meN- verb, like untuk membaca, untuk bekerja, etc.

Could the word order be Pencahayaan di ruang tamu itu untuk membaca nyaman?

No, that word order is unnatural in Indonesian. The normal pattern is:

[subject] + [adjective/adjective phrase]

So:

Pencahayaan di ruang tamu itu (subject)
nyaman untuk membaca (predicate/adjective phrase)

Reordering it as … untuk membaca nyaman breaks the natural flow. If you want to move things around, you could do:

Pencahayaan di ruang tamu itu sangat nyaman untuk membaca.
Untuk membaca, pencahayaan di ruang tamu itu nyaman. (less common but still acceptable, with emphasis on “for reading”)

But … untuk membaca nyaman at the end is not idiomatic.

If I say Pencahayaan di ruang tamu itu enak buat baca, is that acceptable? How does it differ?

Yes, it’s acceptable in informal spoken Indonesian, but note the changes:

nyaman → enak (more colloquial “nice/pleasant”)
untuk → buat (slangy/informal “for”)
membaca → baca (bare root verb, informal)

So:

Pencahayaan di ruang tamu itu nyaman untuk membaca.
- Neutral / standard, suitable for writing, formal or neutral situations.
Pencahayaan di ruang tamu itu enak buat baca.
- Casual, spoken, friendly tone. You’d say this with friends, not in an essay.

The meaning is essentially the same: the lighting is good/pleasant for reading; the difference is just in style and formality.