Learn Hardcore Indonesian: Pohon di halaman belakang sangat tinggi.

So instead of saying “The tree in the backyard is very tall”, Indonesian just puts the parts together: Pohon di halaman belakang sangat tinggi. The linking “is” is simply understood from the structure.

How do I know if pohon means tree (singular) or trees (plural)?

Indonesian nouns usually do not mark singular vs. plural. Pohon can mean tree or trees, depending on context.

If you want to be clear:

pohon – tree / trees (generic)
pohon-pohon – trees (often clearly plural)
banyak pohon – many trees
sebatang pohon – one tree (literally: one “long object” tree)

In Pohon di halaman belakang sangat tinggi, it could be “The tree…” or “The trees…”, depending on what the context has already established.

There’s no the or a in the sentence. How does Indonesian show this?

Indonesian has no separate words that always mean the or a/an. Context usually tells you whether it’s definite (the) or indefinite (a):

Pohon di halaman belakang sangat tinggi.
→ can be understood as “The tree in the backyard is very tall” (if you both know which tree)
or “A tree in the backyard is very tall” (if it’s new information).

If you want to make it clearly “that tree”, you can add itu:

Pohon di halaman belakang itu sangat tinggi.
= That / the tree in the backyard is very tall.

What exactly does di halaman belakang mean, and how is it built?

Di is a preposition meaning in / at / on, depending on context.
Halaman = yard / yard area, belakang = back / behind.

Together:

di (in/at) + halaman belakang (backyard)
→ in the backyard / in the back yard area

Structurally, di halaman belakang is a prepositional phrase telling you where the tree is.

Can I move di halaman belakang to the front or end of the sentence?

Yes. Indonesian word order is flexible for location phrases. All of these are grammatical:

Pohon di halaman belakang sangat tinggi.
Di halaman belakang, pohon sangat tinggi.
Pohon sangat tinggi di halaman belakang. (sounds a bit more like stressing where they’re tall)

The meaning is essentially the same; moving di halaman belakang can add slight emphasis to the location.

What’s the difference between halaman belakang and belakang rumah?

Both can be translated as backyard, but they highlight slightly different ideas:

halaman belakang = back yard area in general (a set phrase for “backyard”)
belakang rumah = the back of the house / area behind the house

Examples:

Pohon di halaman belakang sangat tinggi.
→ The tree(s) in the backyard are very tall.
Pohon di belakang rumah sangat tinggi.
→ The tree(s) behind the house are very tall. (more literal location; maybe not an actual yard)

What is the role of sangat, and can I use sekali instead?

Sangat means very, and it comes before the adjective:

sangat tinggi = very tall

Sekali also means very, but it comes after the adjective:

tinggi sekali = very tall

So you can say:

Pohon di halaman belakang sangat tinggi.
Pohon di halaman belakang tinggi sekali.

Both are natural and mean almost the same thing, though sekali can sound a bit more emphatic or expressive in many contexts.

Is tinggi used for people as well, or only for trees/buildings?

Tinggi is a general adjective for high/tall and is used for:

people: Dia sangat tinggi. → He/She is very tall.
trees: Pohon itu tinggi.
buildings: Gedung itu sangat tinggi.

Context usually tells you whether it’s more like “tall” (vertical length of something) or “high” (e.g., a high place: tempat yang tinggi = a high place).

How would I say “There is a very tall tree in the backyard” instead of “The tree in the backyard is very tall”?

To introduce the existence of something (“there is / there are”), Indonesian commonly uses ada:

Ada pohon yang sangat tinggi di halaman belakang.
= There is a tree that is very tall in the backyard.

Or:

Di halaman belakang ada pohon yang sangat tinggi.
= In the backyard there is a very tall tree.

Your original sentence Pohon di halaman belakang sangat tinggi describes a known tree (or trees), not introduces a new one.

If I want to clearly say “the trees in the backyard are very tall”, how can I make the plural explicit?

You can combine a plural marker with the original structure:

Pohon-pohon di halaman belakang sangat tinggi.
= The trees in the backyard are very tall.

You can also say:

Semua pohon di halaman belakang sangat tinggi.
= All the trees in the backyard are very tall.

Both make it clear that you are talking about more than one tree.