Learn Hardcore Indonesian: Seprai baru di kasur saya lembut sekali. - The new bedsheet on my mattress is very soft.

Indonesian doesn’t use a linking verb in sentences like this. Adjectives can function as predicates. Here, the subject is Seprai baru di kasur saya (“the new sheets on my bed”), and the predicate is lembut sekali (“very soft”). So “are” is simply not expressed.

What does di in di kasur saya mean—“in,” “on,” or “at”? Can I say di atas kasur?

di is a general location preposition (in/on/at, depending on context). With surfaces like a bed, di kasur naturally means “on the bed/mattress.” You can say di atas kasur to be explicitly “on top of the mattress,” but everyday Indonesian often just uses di kasur.

What’s the difference between kasur, ranjang, and tempat tidur?

kasur = the mattress.
ranjang = the bed frame/bedstead.
tempat tidur = the bed (the whole sleeping place). For sheets, di kasur or di tempat tidur are common. di ranjang is also heard when talking about being “in bed.”

Do I need yang before di kasur saya?

No. Noun + prepositional phrase without yang is standard: buku di meja (“the book on the table”). You may add yang for clarity or emphasis: Seprai baru yang di kasur saya lembut sekali, which sounds a bit more explicit/formal but isn’t required.

Where does baru go, and does it mean “new” or “just”?

After a noun, baru means “new”: seprai baru (“new sheets”).
As “just/recently,” baru modifies the clause and comes before the verb/predicate: Saya baru mencuci seprai (“I just washed the sheets”). So in your sentence, baru = “new,” not “just.”

Why is the adjective after the noun (seprai baru) and not before (baru seprai)?

In Indonesian, adjectives typically follow the noun: baju merah, rumah besar, seprai baru. Putting the adjective before the noun is generally ungrammatical or changes meaning. Note that baru can appear before a verb/whole clause when it means “just.”

Is lembut the best word here? How is it different from halus and empuk?

lembut = soft to the touch; also “gentle” (voice/personality).
halus = smooth/fine (no roughness).
empuk = soft/cushiony to sit or lie on. For sheets, lembut or halus both fit. For a mattress/pillow, empuk is more natural.

Why is sekali at the end? Can I use sangat or banget instead?

sekali follows the adjective: lembut sekali (very soft).
sangat precedes it: sangat lembut (also very soft; neutral/formal).
banget is colloquial and goes after: lembut banget (very casual). Don’t combine them (e.g., avoid sangat lembut sekali).

Is the spelling seprai correct? What about sprei or seprei?

Yes, seprai is the standard recommended spelling. sprei is extremely common in everyday Indonesian and widely understood. Avoid seprei in formal contexts.

How can I say “my new sheets” without mentioning the bed?

Use a possessive:

Neutral/formal: seprai baru saya
Informal: seprai baruku Example: Seprai baruku lembut sekali.

How do I make it clearly singular or plural?

Indonesian usually leaves number unmarked. To be explicit:

Singular: selembar seprai (one sheet).
Plural: add a number or quantifier, e.g., dua lembar seprai, beberapa seprai (“some sheets”). Reduplication (seprai-seprai) is possible but less common in speech.

Can I say Seprai baru di kasur saya sangat lembut instead? Is it equally natural?

Yes. sangat lembut and lembut sekali are both natural and mean “very soft.” sangat can sound a touch more formal/neutral; sekali is very common.

Do I need adalah between the subject and the adjective?

No. adalah is typically used to link nouns (e.g., A = B), not before adjectives. So you say Seprai … lembut, not Seprai … adalah lembut.

Why is di kasur saya needed? Could I just say kasur saya?

You need the preposition di to express location. kasur saya alone means “my mattress/bed,” not “on my bed.” di kasur saya = “on my bed.”

Can I use a different possessive, like di kasurku?

Yes:

di kasur saya = neutral/formal.
di kasurku = informal (suffix -ku).
di kasur gue = very informal (Jakarta slang). Keep your register consistent with the rest of the sentence.

How do I show definiteness, like “those/the new sheets on my bed are very soft”?

Add a demonstrative after the noun phrase:

Seprai baru di kasur saya itu lembut sekali (“those/the new sheets on my bed…”). For “these,” use ini instead of itu.

Is there any ambiguity about what’s new—the sheets or the bed? How do I say “The sheets on my new bed are very soft”?

As written, baru most naturally modifies seprai (the sheets). If the bed is new, put baru with kasur: Seprai di kasur baru saya lembut sekali (“The sheets on my new bed are very soft”).

Is di here a preposition or the passive prefix di-?

It’s the preposition di (written separately) indicating location: di kasur. The passive prefix di- attaches to verbs (no space), e.g., dipasang (“installed/put on”), dicuci (“washed”).