Learn Hardcore Indonesian: Dia masih mengantuk di kelas karena tadi malam menonton dua episode serial. - He/She is still sleepy in class because last night he/she watched two episodes of a series.

In practice, mengantuk behaves like a stative verb: it describes a state, but grammatically it’s a verb derived from the noun kantuk (sleepiness).

You can think of:

Dia mengantuk. ≈ “He/She feels sleepy” or “He/She is sleepy.”

Related forms:

kantuk – sleepiness (noun)
mengantuk – to feel sleepy / be sleepy (stative verb)
ngantuk – informal/colloquial form of mengantuk

So Dia masih mengantuk is fully natural for “He/She is still sleepy.”

Why is there no word for “is” in Dia masih mengantuk?

Indonesian normally does not use a separate “to be” verb like English does in this kind of sentence.

Patterns:

English: He is still sleepy.
Indonesian: Dia masih mengantuk. (no separate “is”)

The word mengantuk itself already functions as the predicate (“is sleepy / feels sleepy”).

You also don’t use adalah here. Adalah is mainly used in:

Noun = noun sentences:
- Dia adalah guru. – He/She is a teacher.
Formal definitions:
- Demokrasi adalah sistem pemerintahan…

With feelings or states expressed by verbs or adjectives, you just put them after the subject:

Saya lapar. – I am hungry.
Mereka lelah. – They are tired.

What’s the difference between dia and ia or beliau?

In this sentence: Dia masih mengantuk…

dia
- Most common everyday 3rd-person singular pronoun.
- Gender-neutral: can mean he or she.
- Neutral politeness.
ia
- Also 3rd-person singular, often used in writing, especially more formal or literary style.
- Not used as much in casual speech.
beliau
- Polite/formal pronoun meaning he/she (honorific).
- Used for people you respect (teachers, officials, older people, etc.).

So you could say in a formal context:

Beliau masih mengantuk di kelas… – He/She (respected person) was still sleepy in class…

But for normal conversation and for a generic example sentence, dia is the right choice.

Why is it di kelas and not something like pada kelas or dalam kelas?

di is the basic preposition for location (at/in/on), and kelas is understood as a location (the classroom).

di kelas – in class / in the classroom (most natural)

Other options:

di dalam kelas – literally “inside the classroom”; used when you want to emphasize inside (e.g. as opposed to the corridor).
pada – is used more for abstract locations, times, or targets (e.g. pada hari Senin, pada orang lain). Pada kelas would sound odd here.

So for “sleepy in class,” di kelas is the standard and natural phrase.

What does karena do here, and can the clauses be reversed?

Karena means “because” and introduces the reason clause.

Structure in the sentence:

Dia masih mengantuk di kelas – result
karena tadi malam menonton dua episode serial – reason
- “…because (he/she) watched two episodes of a series last night.”

Yes, you can reverse the order:

Karena tadi malam menonton dua episode serial, dia masih mengantuk di kelas.

Both orders are grammatical.

Starting with karena makes the reason more prominent.
Starting with Dia… puts more focus on the result.

What exactly does tadi malam mean? How is it different from kemarin malam?

Both refer to a past night, but there’s a nuance:

tadi malam
- Literally “earlier tonight.”
- Refers to last night, but with a sense of recentness / just now (from the speaker’s viewpoint).
- Common when speaking the next morning or the same day.
kemarin malam
- Literally “yesterday night.”
- Also means last night, but it treats it more like a full day distance (“yesterday’s night”).

In many casual contexts, both are understood as last night, and people often just use tadi malam when talking the next day, as in this sentence.

Why is dia omitted before menonton in karena tadi malam menonton dua episode serial?

Indonesian often drops the subject in the second clause when it’s obviously the same subject as before.

Full form would be:

Dia masih mengantuk di kelas karena tadi malam dia menonton dua episode serial.

But since it’s clear that “the one who watched” is the same “dia”, speakers usually omit the second dia for natural, less repetitive style:

Dia masih mengantuk di kelas karena tadi malam menonton dua episode serial.

This kind of subject omission is very common in conversational and written Indonesian when there’s no ambiguity.

Is menonton the same as nonton? Which one is better here?

menonton
- Standard, more formal/neutral verb: “to watch.”
- Good for writing, polite speech, and standard sentences.
nonton
- Colloquial, shortened form of menonton.
- Very common in casual speech:
  - Tadi malam aku nonton dua episode.

In this example sentence (which looks like a textbook/neutral sentence), menonton is the better choice. In everyday conversation, people are likely to say nonton instead.

Is dua episode serial natural, or should it be dua episode dari sebuah serial?

Dua episode serial is natural and common in Indonesian, especially in speech and casual writing.

dua episode serial
- Literally “two episodes (of a) series.”
- The relationship “episode-of-serial” is understood without dari.

More explicit or slightly more formal options:

dua episode dari sebuah serial – “two episodes from a series”
dua episode serial TV – “two episodes of a TV series”

But for everyday Indonesian, dua episode serial is perfectly idiomatic and not incorrect.

Can the time phrase tadi malam go at the end instead of before menonton?

Yes. Both word orders are possible and natural:

…karena tadi malam menonton dua episode serial.
…karena menonton dua episode serial tadi malam.

Both mean the same thing.

Putting tadi malam earlier can slightly emphasize the time.
Putting tadi malam at the end sounds very neutral and is also very common.

So you could also say:

Dia masih mengantuk di kelas karena menonton dua episode serial tadi malam.

How do you say “series” in Indonesian? Is serial the only option?

In this sentence, serial is used for “series” (like a TV or streaming series). Common terms:

serial – series, especially TV/online series (very common)
seri – series (also used, sometimes more for books, games, product lines, competitions, etc.)

Examples:

serial drama Korea – Korean drama series
serial Netflix – Netflix series
seri Harry Potter – the Harry Potter series (books/films)

So dua episode serial fits well for “two episodes of a series (show).”