Learn Hardcore Indonesian: Saya menyerahkan tugas akhir kepada guru di perpustakaan. - I hand in the final assignment to the teacher in the library.

aku: more casual/intimate.
gua/gue (Jakarta slang), ane (Betawi), iya/aya (regional): very informal/regional.
For very formal contexts, you’ll still use saya.

So your sentence becomes:

Formal/neutral: Saya menyerahkan…
Casual: Aku menyerahkan… Choose based on who you’re talking to and the setting.

What exactly does the verb menyerahkan mean, and how is it built?

Root: serah (to hand over/submit).
Prefix: meN-
- root starting with s → the s drops and becomes meny-, giving menyerah.
Suffix: -kan (often adds a recipient/beneficiary or makes it causative/applicative).
Result: menyerahkan = to hand over/submit something (often to someone), usually a deliberate, sometimes formal handover.

Important: menyerah (without -kan) means “to surrender/give up,” which is different.

How is menyerahkan different from memberikan and mengumpulkan?

menyerahkan: to hand over/submit, often formal or ceremonial; emphasizes the act of transfer.
memberikan: to give; neutral, everyday “give.”
mengumpulkan: to submit/turn in (assignments, homework) in school/college contexts; literally “to collect,” but idiomatically “to submit” for students. Examples:
Saya menyerahkan/mengumpulkan tugas akhir kepada guru.
Saya memberikan hadiah kepada guru. (“I gave a gift to the teacher.”)

Do I need the preposition kepada here? Why not ke or untuk?

Use:

kepada for recipients (usually people): …kepada guru…
ke for movement to a place: ke perpustakaan (“to the library”).
untuk for purpose/benefit (“for”): tugas untuk guru = “a task for the teacher (intended for).” In informal speech, some say ke guru, but standard Indonesian prefers kepada for recipients.

Does di perpustakaan describe where the handing-over happened, or which teacher (the one in the library)?

It’s ambiguous as written. It can mean: 1) The handover happened at the library. 2) The teacher is (the one) at the library.

To disambiguate:

Place of action: Di perpustakaan, saya menyerahkan tugas akhir kepada guru.
Teacher’s location: Saya menyerahkan tugas akhir kepada guru yang berada di perpustakaan.

Is guru definite (“the teacher”) or indefinite (“a teacher”)? How do I say “my teacher”?

Indonesian has no articles, so guru can be definite or indefinite from context.

Explicit definite: guru itu (“that/the teacher”), gurunya (“the teacher already known”).
Possessive: guru saya or guruku (“my teacher”).
With a title: kepada Pak/Bu [Name] (Mr./Ms.) is polite and common.

Can I move the location to the front of the sentence?

Yes. Very natural:

Di perpustakaan, saya menyerahkan tugas akhir kepada guru. You can also keep it at the end; Indonesian is flexible with adverbials of place.

How do I talk about time or completion (past/future) since Indonesian has no tenses?

Add time/aspect markers:

Completed: Saya sudah menyerahkan… or formal Saya telah menyerahkan…
Ongoing: Saya sedang menyerahkan… (rare for this verb).
Future: Saya akan menyerahkan…
Time words: tadi (earlier), kemarin (yesterday), besok (tomorrow). Example: Kemarin saya sudah menyerahkan tugas akhir kepada guru di perpustakaan.

Is guru the right word at university level?

In schools: guru (teacher). In universities: dosen (lecturer). So you’d say:

Saya menyerahkan tugas akhir kepada dosen di perpustakaan.

What exactly does tugas akhir mean? Is it a final assignment or a thesis?

It depends on context:

In general: “final assignment/project.”
At many Indonesian universities: tugas akhir can refer to the capstone project, often a thesis-equivalent (sometimes specifically called skripsi for undergrad, tesis for master’s, disertasi for doctoral). Context (school vs university) clarifies it.

How do I ask “To whom did you submit it?”

Neutral: Kepada siapa kamu menyerahkannya?
Polite/formal: Kepada siapa Anda menyerahkannya? Here -nya on menyerahkannya stands for “it” (the thing submitted).

How do I say “at the campus library” or specify which library?

Add a descriptor:

di perpustakaan kampus (at the campus library)
di perpustakaan sekolah (at the school library)
di perpustakaan itu (at that/the library already known)

Is it okay to omit the recipient?

Yes, if context makes it clear:

Saya menyerahkan tugas akhir. You can also omit the object if the focus is on the recipient:
Saya menyerahkan kepada guru. (sounds incomplete unless the object is obvious from context)

What does the suffix -kan contribute in menyerahkan?

With serah, adding -kan (and meN-) yields a verb that:

takes a direct object (what you hand over)
and typically an oblique recipient with kepada (to whom) So menyerahkan X kepada Y = hand over X to Y. Without -kan, menyerah means “to surrender,” which is intransitive and different in meaning.

Can I use pada instead of kepada?

In formal writing, you’ll see pada used with human recipients, but the more standard, unambiguous choice is kepada. So:

Formal: …pada guru… (acceptable)
Neutral standard: …kepada guru… (preferred)

Should it be di perpustakaan or ke perpustakaan?

di perpustakaan = at/in the library (location).
ke perpustakaan = to the library (movement/direction). Your sentence describes where the handover happened, so di is correct.

How do I say this in the passive voice?

Common passive (focus on the object):

Tugas akhir saya diserahkan kepada guru di perpustakaan. (agent unspecified) If you include the agent:
Tugas akhir saya diserahkan oleh saya kepada guru di perpustakaan. (grammatical but often people avoid repeating saya like this) More natural with agent fronted:
Saya menyerahkan tugas akhir kepada guru di perpustakaan. (active) Topicalized object in active (common in Indonesian):
Tugas akhir saya saya serahkan kepada guru di perpustakaan.

What would a colloquial version sound like?

In casual Jakarta-style speech:

Aku ngasih/nyerahin tugas akhir ke guru di perpustakaan. Notes:
ngasih = give (colloquial; from kasih).
nyerahin = colloquial for menyerahkan (with -in variant).
ke guru appears in colloquial speech instead of kepada guru. Use with care in formal settings.

Is there a polite way to refer to the teacher?

Yes, use titles:

kepada Pak/Bu Guru (Mr./Ms. Teacher)
With a name: kepada Pak Andi / Bu Sari This is common and polite in schools.