Learn Hardcore Indonesian: Keringatnya menetes perlahan-lahan saat dia minum air hangat. - His/Her sweat drips slowly as he/she drinks warm water.

Keringatnya menetes … saat dia minum …
Keringatnya menetes … saat minum … Dropping the pronoun is common when the subject is clear from context.

What’s the difference between saat, ketika, waktu, sementara, and sambil?

saat / ketika: both mean “when.” Ketika can feel slightly more formal; both are fine.
waktu: conversational “when” (literally “time”), also fine: waktu dia minum…
sementara: “while,” often contrasting simultaneous actions with different subjects.
sambil: “while (doing something else)” with the same subject: Dia minum sambil membaca.

Why menetes and not tetes?

tetes is a noun (“a drop”).
menetes is the intransitive verb “to drip/fall in drops.” So Keringatnya menetes = “The sweat drips.”

What’s the difference between menetes and meneteskan?

menetes: intransitive (no direct object). Example: Keringatnya menetes ke lantai.
meneteskan: transitive (takes an object), “to let/drop something in drops.” Example: Dia meneteskan obat mata. You usually wouldn’t say meneteskan keringat unless you mean deliberately causing sweat to drip somewhere.

Is perlahan-lahan the same as perlahan or pelan-pelan?

perlahan-lahan and perlahan: standard/neutral “slowly,” “gradually.”
pelan-pelan: very common and more colloquial.
pelan: “slow,” also used adverbially.
lambat: “slow” for speed/processes; less natural for a dripping action. Spelling note: reduplication takes a hyphen: perlahan-lahan, pelan-pelan.

Where can I place perlahan-lahan in the sentence?

Flexible:

Default: Keringatnya menetes perlahan-lahan.
Fronted for emphasis: Perlahan-lahan, keringatnya menetes.
Between subject and verb is also possible: Keringatnya perlahan-lahan menetes. All are natural.

Does air hangat mean hot water?

No. air hangat = warm water (comfortable to the touch). air panas = hot/near boiling. Other pairs: air dingin (cold water), teh hangat (warm tea), air putih (plain drinking water).

Is minum different from meminum?

minum is the everyday verb “to drink,” and it can take an object: minum air.
meminum is more formal/explicitly transitive; you’ll see it in writing, instructions, or when emphasizing the act: meminum obat. In daily speech, minum is preferred.

Is dia gendered? Could I use ia or beliau instead?

dia is gender-neutral (he/she).
ia is common in formal writing, mostly as a subject.
beliau is an honorific “he/she” for respected elders or officials. All three are third-person; choose based on register and respect.

Could I say Dia berkeringat saat minum air hangat?

Yes. berkeringat = “to sweat (be sweating).”

Keringatnya menetes focuses on drops falling.
Dia berkeringat states the condition of sweating. Both are natural; they differ in emphasis.

Do I need sedang to show the progressive aspect?

Not required, but you can add it for emphasis on an ongoing action:

saat dia minum (neutral)
saat dia sedang minum (clearly “while he/she was in the middle of drinking”)

Any pronunciation tips for -nya, ng, and the vowels here?

ny in -nya is a single sound [ɲ], like Spanish ñ: “nya.”
ng in hangat is [ŋ], as in “sing.”
In menetes, the first e is the schwa [ə] (meh-), the second e is clearer [e] (…-NE-tes). Indonesian stress is light, typically near the end.

Is the comma needed if I put the time clause first?

Yes, if the time clause comes first, use a comma:

Saat dia minum air hangat, keringatnya menetes perlahan-lahan. No comma is needed in the original order.