Learn Hardcore Indonesian: Jangan minum kopi banyak-banyak sebelum tidur. - Don't drink too much coffee before sleeping.

Use jangan when you are telling or asking someone not to do something.
Use tidak when you are stating that something is not true / not happening.

In Jangan minum kopi banyak-banyak sebelum tidur, jangan is correct because it’s giving a prohibition or advice: Don’t drink…

Where is the word “you” in this sentence? Why is there no kamu or Anda?

In Indonesian, the subject “you” is often left out in imperatives because it’s understood from context. Imperatives normally target the listener automatically.

Jangan minum kopi.
Literally: Don’t drink coffee.
Implied: (You) don’t drink coffee.

If you want to be explicit, you can add a pronoun:

Jangan kamu minum kopi banyak-banyak sebelum tidur.
Kamu jangan minum kopi banyak-banyak sebelum tidur.

These are grammatically correct, but they can sound:

more emphatic, or
slightly more scolding, depending on tone.

For polite, neutral advice, the simple form Jangan minum kopi banyak-banyak sebelum tidur is very natural.

Why is banyak-banyak repeated? What’s the difference between banyak and banyak-banyak?

The repetition (reduplication) of banyak to banyak-banyak adds emphasis and a sense of “a lot / in large amounts”, often with a flavor of “too much” in context.

banyak = many / much
banyak-banyak = a lot, in large amounts, “really a lot (don’t overdo it)”

In this sentence:

minum kopi banyak-banyak ≈ drink a lot of coffee / drink coffee in large amounts

Because the sentence is a warning, banyak-banyak is understood as “don’t drink too much coffee”, even though there is no word terlalu (“too”) in the sentence.

If you just said:

Jangan minum kopi banyak sebelum tidur.

it would still be understood, but banyak-banyak is:

more natural,
more colloquial, and
has a slightly stronger feel of “don’t overdo it.”

Can I say terlalu banyak or kebanyakan instead of banyak-banyak? What’s the difference?

Yes, you can, but the nuance changes a bit:

banyak-banyak
- Feels informal and spoken.
- Emphasizes “a lot / large amounts,” often implying “too much” in context.
- Jangan minum kopi banyak-banyak sebelum tidur.
  ≈ Don’t drink a lot of coffee before sleeping (don’t overdo it).
terlalu banyak (literally: “too many / too much”)
- More explicit about excess.
- Slightly more neutral / less colloquial.
- Jangan minum kopi terlalu banyak sebelum tidur.
  = Don’t drink too much coffee before sleeping.
kebanyakan (can mean “too much / too many” or “usually/mostly”, depending on context)
- As “too much/too many” with verbs or nouns:
  - Jangan kebanyakan minum kopi sebelum tidur.
    = Don’t drink too much coffee before sleeping.
- This is also very common, natural, and colloquial.

All three are acceptable, but:

banyak-banyak and kebanyakan feel more informal / conversational.
terlalu banyak sounds a bit more straightforward and explicit about “too much.”

Why is it minum kopi banyak-banyak and not minum banyak-banyak kopi?

The usual, most natural word order is:

Verb – Object – Modifier
minum – kopi – banyak-banyak

So:

minum kopi banyak-banyak = drink coffee in large amounts.

You can see banyak-banyak placed before the noun in other structures, but here:

minum banyak-banyak kopi sounds awkward or wrong to native speakers.
banyak-banyak is really modifying the action of drinking (the amount drunk), and by extension the object. The standard pattern for this type is after the noun/object.

A more natural alternative word order that still sounds good is:

Jangan banyak-banyak minum kopi sebelum tidur.

Here, banyak-banyak comes before the verb phrase, modifying the degree of the action minum kopi as a whole:
“Don’t too-much drink coffee before sleeping.” (i.e., Don’t drink coffee too much.)

What does sebelum tidur literally mean? Is tidur a noun or a verb here?

Literally:

sebelum = before
tidur = sleep / to sleep

Indonesian doesn’t separate nouns and verbs as strictly as English. Tidur can function as:

a verb:
- Saya mau tidur. = I want to sleep.
a noun-like element in time expressions:
- sebelum tidur = before sleeping / going to sleep

In Jangan minum kopi banyak-banyak sebelum tidur, sebelum tidur means:

before sleeping
before you go to bed

So you can think of tidur here as a verb in a non-finite form (“sleeping”) or a noun-like event (“sleep time”). Indonesian doesn’t need an extra form like “to sleep / sleeping / sleep”; tidur covers it.

Can I say sebelum kamu tidur instead of sebelum tidur? Is there a difference?

Yes, you can say:

Jangan minum kopi banyak-banyak sebelum kamu tidur.

This is grammatically correct and still natural. The differences:

sebelum tidur
- More generic and shorter.
- Very common in instructions, advice, or general rules.
- Implies “before (you) sleep” without saying kamu.
sebelum kamu tidur
- More personal and explicit.
- Often used when talking to a specific person, especially in spoken language:
  - A parent to a child,
  - A doctor to a patient, etc.

Both are fine. Leaving out kamu is very normal and often sounds smoother unless you really want to emphasize you specifically.

Is this sentence formal or informal? How would I make it more polite or more casual?

Jangan minum kopi banyak-banyak sebelum tidur is:

Neutral-informal: perfectly okay in everyday conversation.
Not rude, but not very formal either.

To make it more polite/formal, you could:

Jangan minum kopi terlalu banyak sebelum tidur.
(Using terlalu banyak instead of banyak-banyak feels a bit more neutral.)
Or, if you must mark a formal “you”:
- Sebaiknya Anda tidak minum kopi terlalu banyak sebelum tidur.
  (“It’s better that you don’t drink too much coffee before sleeping.”)
  This is polite and softened.

To make it more casual/colloquial, you could add particles:

Jangan minum kopi banyak-banyak sebelum tidur ya.
“Okay?/alright?” – softens the tone.
Jangan minum kopi banyak-banyak sebelum tidur dong.
More emphatic, as if saying “Come on, don’t do that.”

Particles like ya, dong, deh, lah adjust the tone (gentle, pleading, friendly, etc.) but don’t change the basic meaning.

Does kopi here mean “a cup of coffee” or “coffee in general”? Do I need a word like secangkir?

In this sentence, kopi means coffee in general, not a specific cup.

Indonesian often uses bare nouns for general substances:

Saya minum kopi. = I drink coffee. (not necessarily one cup, just the beverage)
Dia tidak minum susu. = He/She doesn’t drink milk.

If you want to specify a unit (a cup, a glass, etc.), you add a classifier:

secangkir kopi = a cup of coffee
segelas kopi = a glass of coffee (e.g., iced)
dua cangkir kopi = two cups of coffee

You could say:

Jangan minum dua cangkir kopi sebelum tidur.
= Don’t drink two cups of coffee before sleeping.

But in the original sentence, the focus is on the amount in general, so plain kopi is correct and natural.

Is jangan always so strong, like a strict command? Can it be softer, like a suggestion?

Jangan can range from:

a strong prohibition (“Don’t do that!”), to
a gentle piece of advice (“You’d better not…”),

depending on tone of voice, context, and sometimes added words.

In Jangan minum kopi banyak-banyak sebelum tidur, it will usually be heard as advice or a warning, not angry shouting, especially in a context like health, sleep habits, or friendly advice.

To soften it further, speakers often:

add a softener:
- Jangan minum kopi banyak-banyak sebelum tidur ya.
or use a more indirect structure:
- Sebaiknya jangan minum kopi banyak-banyak sebelum tidur.
  (“It’s better not to drink a lot of coffee before sleeping.”)

So jangan is not automatically “harsh”; it’s the standard way to say “don’t …”, and the tone is shaped by context and added words.