Learn Hardcore Indonesian: Rokmu hijau, dan sandalku hitam. - Your skirt is green, and my sandals are black.

-mu = your (2nd person singular), as in rokmu (your skirt).
-ku = my (1st person singular), as in sandalku (my sandals). They attach to the noun with no space: write rokmu, sandalku (not “rok mu” or “sandal ku”).

How formal are -mu and -ku? What are alternatives?

They’re neutral-to-informal and very common. Alternatives:

Neutral/informal separate pronouns: rok kamu, sandal kamu.
More formal/polite: rok Anda, sandal saya.
Very neutral “my” with a separate pronoun: sandal saya instead of sandalku.

Can I ever write them with a hyphen or separately?

Standard spelling attaches them directly with no hyphen or space: sandalku, rokmu.
Exception: if the noun is reduplicated for plural, keep the hyphen of reduplication and attach the clitic to the second copy, e.g., sandal-sandalku, buku-bukumu.

Where is the verb “is/are”? Why can Indonesian say Rokmu hijau without it?

Indonesian typically omits the copula (“to be”) in the present tense when the predicate is an adjective or a noun phrase. So Rokmu hijau literally “Your skirt green” means “Your skirt is green.” Likewise, Sandalku hitam = “My sandals are black.”

Can I say Rokmu adalah hijau?

No—using adalah with an adjective is ungrammatical/unnatural. Use:

Rokmu hijau. (natural)
Rokmu berwarna hijau. (has the color green; slightly more formal)

What’s the adjective word order? Why not hijau rokmu?

Attributive (modifying a noun): adjective follows the noun, e.g., rok hijau = a green skirt, sandal hitam = black sandals.
Predicative (as a sentence): subject + adjective, e.g., Rokmu hijau, Sandalku hitam.
So hijau rokmu is not how Indonesian expresses either pattern.

Is sandalku singular or plural?

Indonesian usually doesn’t mark number, so sandalku can mean “my sandal” or “my sandals” (context decides; a pair is typically understood). To make plural explicit, you can use reduplication: sandal-sandalku (my sandals), or use a numeral/classifier: sepasang sandal saya (a pair of my sandals).

Do I need the comma before dan here?

No. The standard is without a comma: Rokmu hijau dan sandalku hitam. A comma can mark a deliberate pause in speech, but most style guides omit it before dan.

How do I negate these sentences?

Use tidak before adjectives:

Sandalku tidak hitam. (My sandals are not black.)
Rokmu tidak hijau. (Your skirt is not green.) Use bukan when negating a noun phrase: Itu bukan rok (That is not a skirt).

How do I ask “Is your skirt green?”

Rokmu hijau? (rising intonation; common in speech)
Apakah rokmu hijau? (more formal/explicit yes–no question)

How can I ask “What color is your skirt?”

Natural options:

Rokmu berwarna apa?
Apa warna rokmu?
Rokmu warnanya apa? (colloquial)

Are color words inflected for number or gender?

No. Adjectives like hijau and hitam never change for number or gender. They stay the same with singular/plural, masculine/feminine, etc.

How do I say “very” or “-ish” with colors?

“Very”: sangat (before) or sekali (after): Rokmu sangat hijau / Rokmu hijau sekali. Colloquial: banget (after): Rokmu hijau banget.
“-ish”: use the prefix ke- -an: kehijauan (greenish), kehitaman (blackish): Rokmu kehijauan.

What’s the third-person possessive equivalent (his/her/its)?

Use -nya or a separate pronoun:

sandalnya hitam = his/her sandals are black.
sandal dia hitam is also possible (less compact).
-nya is the most common.

Any pronunciation tips for these words?

rokmu: the final k in rok is often realized as a glottal stop in casual speech; syllables roughly “rok-mu.”
sandalku: syllables “san-dal-ku.”
Vowels are pure: u like “oo” in “food,” a like “a” in “father.”

Does Indonesian have articles like “a/the”? How would I say “the skirt” or “a skirt”?

Indonesian has no articles. Use context or demonstratives:

“this/that”: rok ini/rok itu.
If you must stress “a/one,” you can use sebuah rok (one/a skirt), though counting words are often omitted unless needed.