Learn Hardcore Indonesian: Saya ingin pulang cepat; sebaliknya, dia memilih melanjutkan rapat. - I want to go home quickly; on the contrary, he/she chooses to continue the meeting.

pulang = to go/return home (to one’s home base). It implies “home” even if you don’t say rumah.
pergi = to go (away), with no implication of returning or of “home.”
balik/kembali = to return/go back (to a previous place), not necessarily home. balik is more casual; kembali is neutral/formal.
Examples: Saya pulang. (go home) vs Saya kembali ke kantor. (go back to the office)

In this context, does cepat mean “fast” or “early”?

With pulang, cepat often means “early” (leaving earlier than usual/scheduled), not literally “at high speed.”
To stress speed, use dengan cepat, cepat-cepat, or terburu-buru.
For “early” in a schedule sense, lebih awal is unambiguous: pulang lebih awal = leave early.
segera = soon/at once (time proximity), not necessarily “earlier than planned.”

Is Saya ingin pulang cepat as natural as Saya ingin cepat pulang? Any difference?

Both are natural. Indonesian allows adverbs like cepat before or after the verb.
Nuance is minimal; many speakers find ingin cepat pulang a touch more idiomatic in speech.
If you mean “earlier than scheduled,” ingin pulang lebih awal is the clearest.

What’s the nuance difference between ingin and mau here?

ingin = want/desire, slightly more formal/polite and common in writing or professional settings.
mau = want, very common and neutral in everyday speech (not rude).
Colloquial alternatives: pengen/pingin/pengin (very casual).

Is dia gendered? When would I use ia or beliau instead?

dia is gender-neutral (“he/she/they (singular)”).
ia is mostly written/literary and typically used as a subject (you wouldn’t say saya melihat ia, but saya melihatnya).
beliau is a respectful third-person pronoun for elders/superiors.
To specify gender, add a noun: dia (laki-laki/pria) or dia (perempuan/wanita).

Why memilih melanjutkan and not memilih untuk melanjutkan? Are both correct?

Both are correct. memilih melanjutkan and memilih untuk melanjutkan are natural.
untuk is optional before a verb complement and can add a slight sense of formality or clarity.
Parallel examples: Dia memilih bekerja dari rumah / Dia memilih untuk bekerja dari rumah.

What’s the difference among melanjutkan, lanjut, and meneruskan?

melanjutkan (transitive): to continue something (takes an object) — melanjutkan rapat.
lanjut: base form; in colloquial speech can function as a verb/adjective/adverb — lanjut rapat (casual: “continue the meeting”).
meneruskan (transitive): near-synonym of melanjutkan, often “to carry on” or “to resume.” In casual speech: nerusin; for melanjutkan: lanjutin.

How does sebaliknya differ from tetapi/tapi, sedangkan, and sementara?

sebaliknya = conversely/on the other hand; highlights an opposing or contrasting alternative. Often starts a clause: Sebaliknya, …
tetapi/tapi = but; a general contrast connector.
sedangkan = whereas/while (contrast between two subjects or situations in parallel).
sementara = while (temporal “at the same time” nuance), sometimes contrastive depending on context.

Is the semicolon before sebaliknya necessary? How about the comma after it?

The semicolon is stylistically appropriate in formal writing to join two closely related independent clauses. A period or , tetapi would also be fine.
The comma after sebaliknya is standard because sebaliknya acts like a sentence adverb/discourse marker.
Acceptable variants:
- Saya ingin pulang cepat. Sebaliknya, dia memilih melanjutkan rapat.
- Saya ingin pulang cepat, tetapi dia memilih melanjutkan rapat.
- Saya ingin pulang cepat, sedangkan dia memilih melanjutkan rapat.

Should it be rapat or rapatnya?

rapat is fine when the meeting is understood from context (generic/ongoing meeting).
rapatnya can mean “the meeting” (definite) or “his/her meeting” (possessive), depending on context. Use it if you’ve already identified a specific meeting or want to mark definiteness.

Is pulang cepat ever ambiguous? How do I remove ambiguity?

It can be read as “go home early” or “go home quickly.” Context usually resolves it.
To be explicit:
- Early: pulang lebih awal, pulang lebih cepat dari biasanya.
- Quickly/in a hurry: pulang dengan cepat, cepat-cepat pulang, pulang terburu-buru.

What would a casual, conversational version of the whole sentence look like?

Jakarta-style casual: Gue pengin pulang cepet, tapi dia milih lanjut rapat.
Neutral casual: Aku mau pulang lebih awal, sedangkan dia milih lanjut rapat.
Even shorter colloquial: Gue pengin cepet pulang, dia masih lanjut rapat.

How would I make the first clause more polite in a workplace setting?

Bolehkah saya pulang lebih awal?
Saya mohon izin pulang lebih awal.
You can keep the contrast if needed: Saya mohon izin pulang lebih awal; sebaliknya, dia memilih melanjutkan rapat. (very formal)

Does the sentence specify when this happens? How would I add time?

Indonesian doesn’t mark tense morphologically; add time words for clarity:
- Past: Tadi saya ingin pulang cepat; sebaliknya, dia memilih melanjutkan rapat.
- Today/plan: Hari ini saya ingin pulang lebih awal; …
- Soon: Saya ingin segera pulang; … (soon, not necessarily “earlier than planned”).