Learn Hardcore Indonesian: Kamulah yang memilih waktu presentasi, bukan saya. - You are the one who chose the presentation time, not me.

It adds focus/emphasis. Kamulah yang ... works like an English cleft: “It was you who …”. It highlights kamu as the focused element, contrasting it with bukan saya.

Do I have to write Kamulah as one word? Is Kamu lah acceptable?

Write it as one word: Kamulah. -lah is a clitic that attaches to the preceding word. Writing Kamu lah is nonstandard.

Is Kamulah the same as Kaulah?

No. Kamulah = kamu + -lah; Kaulah = kau + -lah. Kamu and kau are both “you (sing.)”, but kau is more literary/poetic and regionally common; kamu is the usual informal pronoun.

Why is yang used here?

Yang introduces a clause that modifies the focused noun/pronoun. Kamulah yang memilih ... literally “You are the one who chose ...”. Without yang, you lose the cleft/focus structure.

Can I drop -lah and just say Kamu yang memilih waktu presentasi, bukan saya?

Yes. That’s natural, especially in speech. -lah adds a touch of emphasis/formality, but Kamu yang ... already focuses on kamu.

Can I say the sentence without yang?

You can say Kamu memilih waktu presentasi, bukan saya, and it’s fine. It states the fact but with less “It was you who …” focus than the yang-cleft.

Why is it bukan saya, not tidak saya?

Use bukan to negate nouns/pronouns and noun phrases; use tidak to negate verbs, adjectives, and adverbs.

Correct: bukan saya, bukan guru itu
Correct: tidak memilih, tidak cepat Here, saya is a pronoun, so bukan is required.

What’s the nuance difference between bukan saya and bukannya saya?

Bukannya saya sounds like you’re rejecting a prior assumption (“It’s not me (as you might think)”). It’s slightly more contrastive. Both are grammatical: ..., bukan saya is the neutral default; ..., bukannya saya is stronger rhetorically.

Should I use saya or aku here?

Both mean “I/me.” Saya is neutral/polite; aku is intimate/informal. Be consistent with your register:

Polite/neutral: Kamulah yang memilih ..., bukan saya.
Casual: Kamu yang pilih ..., bukan aku.

Can I front the negation: Bukan saya yang memilih waktu presentasi?

Yes. Bukan saya yang memilih waktu presentasi; kamu. This focuses on denying your involvement. It’s common and natural.

Can I also put -lah on the negation, like Bukanlah saya?

Yes, for added emphasis/formality: Bukanlah saya yang memilih .... Similarly, Andalah yang memilih ... is a polite version with Anda.

What’s the difference between memilih and pilih?

Memilih is the standard meN- verb form. In casual speech, Indonesians often drop the prefix: pilih.

Formal/neutral: yang memilih
Casual: yang pilih

Does memilih mark past tense here?

Indonesian doesn’t have tense marking. Memilih is tenseless; context gives time. To be explicit:

Past/completed: yang sudah memilih, yang tadi memilih
Future: yang akan memilih, yang mau memilih

Is waktu presentasi the best phrase? What about jadwal or jam?

waktu presentasi: the time/time slot of the presentation (general).
jam presentasi: the clock time (e.g., 10:30).
jadwal presentasi: the schedule (possibly multiple times/sequence).
waktu untuk presentasi: “time for presenting” (slightly more formal/explanatory). Choose based on what you mean.

Is the comma before bukan saya required?

It’s recommended to mark the contrast. You’ll also see a dash or semicolon in writing. In speech, a short pause plays the same role.

How would I say this in very formal and very casual styles?

Very formal: Andalah yang memilih waktu presentasi, bukan saya. or Yang memilih waktu presentasi adalah Anda, bukan saya.
Very casual (Jakarta): Lo yang milih waktu presentasi, bukan gue.

Any pronunciation tips?

yang ends with the velar nasal [ŋ] (like “sing”).
-lah is unstressed; it doesn’t add a syllable break.
presentasi typically has a schwa-like first e: roughly /prә-sen-TA-si/. Indonesian has relatively even stress compared to English.