Talang di atap tersumbat oleh daun basah.

Talang usually means a gutter or drain channel that carries rainwater away. In a house-related sentence like this, it most naturally means the roof gutter.

So talang di atap is essentially the gutter on the roof.

Because this di is a preposition, meaning in / on / at.

• di atap = on the roof
• di rumah = at home
• di jalan = on the street

In Indonesian, di is written separately when it shows location.

This is different from di- as a passive prefix, which is attached to a verb:

• ditutup = closed / was closed
• dibuka = opened / was opened

So:

• di atap → separate, because it is a location phrase
• ditutup → attached, because it is part of a verb

Sumbat relates to blocking or clogging.
Tersumbat means blocked, clogged, or jammed up.

The prefix ter- often describes a state or a condition that has happened, rather than focusing on who did it. Here, tersumbat describes the gutter as being in a clogged state.

So tersumbat is not exactly the same as an ordinary active verb like menyumbat (to clog). It emphasizes the result:

• daun basah menyumbat talang = wet leaves clog the gutter
• talang tersumbat = the gutter is clogged

In this sentence, tersumbat works very naturally because we are describing the condition of the gutter.

Yes, it is basically passive in meaning, or at least strongly patient-focused.

The sentence focuses on talang—the thing affected—rather than on the leaves as the main actor.

• Talang di atap tersumbat oleh daun basah. = The gutter on the roof is clogged by wet leaves.

An active version would be:

• Daun basah menyumbat talang di atap. = Wet leaves clog the gutter on the roof.

Indonesian often prefers structures like tersumbat when describing a resulting condition.

Oleh means by, and it introduces the cause or agent in a passive-style sentence.

So:

• tersumbat oleh daun basah = clogged by wet leaves

It is grammatical and clear. However, in everyday Indonesian, oleh is often omitted if the meaning is obvious.

For example, people might also say:

• Talang di atap tersumbat daun basah.
• Talang di atap tersumbat karena daun basah.

These have slightly different feels:

• oleh daun basah = by wet leaves
• karena daun basah = because of wet leaves

Using oleh is correct and explicit, but not always required in casual speech.

Because in Indonesian, adjectives usually come after the noun.

So:

• daun basah = wet leaves
• rumah besar = big house
• air dingin = cold water

This is the normal word order:

• noun + adjective

So daun basah is the expected structure.

Indonesian often does not require plural marking when the meaning is already clear from context.

So daun can mean:

• leaf
• leaves

In this sentence, real-world context makes leaves the natural interpretation, because gutters are usually clogged by more than one leaf.

If you wanted to make plurality explicit, you could say:

• daun-daun basah = wet leaves

But Indonesian often leaves nouns unmarked for number unless it matters.

So daun basah here is perfectly natural.

Because Indonesian does not normally use articles like a, an, or the.

That means a noun like talang can mean:

• a gutter
• the gutter

The exact meaning depends on context.

In this sentence, English naturally uses the gutter because it sounds specific, but Indonesian does not need a separate word for that.

This is very common in Indonesian:

• rumah = house / a house / the house
• buku = book / a book / the book

Context does the work.

In normal interpretation, di atap describes talang:

• talang di atap = the gutter on the roof

So the whole noun phrase is:

• talang di atap → the roof gutter / the gutter on the roof

Then the rest says that this gutter is clogged.

So the structure is basically:

• Talang di atap = the gutter on the roof
• tersumbat oleh daun basah = is clogged by wet leaves

Even though you could theoretically read di atap as a location phrase for the whole situation, the most natural reading is that it specifies which talang we are talking about.

Yes. A natural active version is:

• Daun basah menyumbat talang di atap.

Here:

• daun basah = subject
• menyumbat = clog / block
• talang di atap = object

The difference is focus:

• Talang di atap tersumbat oleh daun basah.
  Focuses on the gutter and its condition.
• Daun basah menyumbat talang di atap.
  Focuses on the wet leaves doing the clogging.

Both are correct, but the original sounds especially natural if you are reporting the problem with the gutter.

Not always. It often refers to something being blocked, clogged, or obstructed, and it can be used both literally and figuratively.

Literal examples:

• Saluran air tersumbat. = The drain is clogged.
• Hidung saya tersumbat. = My nose is blocked.

So in your sentence, it is a very typical literal use: a gutter is physically blocked by wet leaves.

The original sentence is correct and natural. But in everyday speech, people might also say things like:

• Talang di atap tersumbat karena daun basah.
• Talang atapnya tersumbat daun basah.
• Talangnya tersumbat oleh daun basah.

These versions differ a little in style, but they all communicate the same basic idea.

The original version is nice because it is clear, grammatical, and easy for learners to analyze.