Learn Hardcore Indonesian: Mentor yang lain melatih keterampilan menulis lamaran kerja. - Another mentor trains the skill of writing a job application.

lain = other / different
yang turns lain into a clause-like modifier referring back to mentor: mentor [who is] other (than the one already mentioned).

You can say mentor lain, and it’s also correct, but:

mentor yang lain tends to feel a bit more specific, like “that other mentor (we already know about)”.
mentor lain can sound slightly more general: “another mentor / a different mentor”, not necessarily one already introduced.

In many real contexts, both are interchangeable and the difference is subtle or depends on the wider context.

Is mentor here singular or plural? Does mentor yang lain mean “the other mentor” or “the other mentors”?

Indonesian nouns usually have no explicit singular/plural marking. Mentor by itself can mean mentor or mentors.

So mentor yang lain can mean:

the other mentor (singular), or
the other mentors (plural).

Which one is meant depends on context, for example:

If previously one mentor was mentioned, mentor yang lain is likely “the other mentor” (singular).
If a group of mentors is being contrasted with another group, mentor yang lain could be “the other mentors” (plural).

To make plural explicit, people sometimes add para:

Para mentor yang lain = the other mentors (clearly plural).

What is the difference between melatih and mengajar? Could we say mengajar keterampilan menulis lamaran kerja?

Both are related to teaching, but they’re not identical:

melatih = to train, to coach, to drill (emphasis on practicing a skill)
mengajar = to teach (emphasis on giving instruction/lessons)

In this sentence:

melatih keterampilan menulis lamaran kerja suggests the mentor is training students’ practical skills in writing job applications (giving exercises, practice, feedback, etc.).

You could say:

mengajar cara menulis lamaran kerja = teaches how to write job applications
mengajar keterampilan menulis = teaches writing skills

But melatih keterampilan sounds especially natural when you are focusing on skill-building through practice, which fits keterampilan (“skills”) very well.

How is melatih formed, and what’s the difference between latih, melatih, berlatih, and latihan?

Root: latih (train)

From this root, you get:

melatih = to train (someone)
- me- prefix → active transitive verb
- Example: Mentor melatih siswa. = The mentor trains the students.
berlatih = to practice / to train (yourself)
- ber- prefix → intransitive / doing the activity
- Example: Mereka berlatih setiap hari. = They practice every day.
latihan = practice / exercise (noun)
- -an suffix → noun
- Example: latihan menulis = writing practice / exercise

In the sentence melatih keterampilan menulis lamaran kerja, melatih is the active verb: the mentor (subject) is training someone’s skills.

What exactly does keterampilan menulis mean? Is menulis a verb or something like a noun here?

keterampilan menulis literally is “skill(s) [of] writing”.

keterampilan = skill(s), ability (noun)
menulis = to write / writing (verb form acting like a noun here)

In English we treat writing as a gerund in “writing skills”. In Indonesian, the me- verb form (menulis) can follow a noun to indicate the type of skill:

keterampilan menulis = writing skills
keterampilan berbicara = speaking skills
keterampilan mendengar = listening skills

So menulis is grammatically still a verb form, but in this position it functions like a descriptor, similar to English gerunds (writing, speaking, etc.).

How is keterampilan formed, and is it different from skill words built with -ke-an in general?

keterampilan is derived from:

terampil = skilled, skillful
ke-…-an → keterampilan = skill, skillfulness, skill set

So:

terampil (adj) → keterampilan (noun)

The ke-…-an pattern often turns adjectives or roots into abstract nouns:

tinggi → ketinggian (height)
adil → keadilan (justice)
miskin → kemiskinan (poverty)

Here, keterampilan is a very common word meaning skills, especially practical or professional skills.

What does lamaran kerja literally mean, and how is it structured?

lamaran kerja is a noun phrase:

lamaran = application (for a job, scholarship, etc.)
- from the root lamar = to apply / to propose (for marriage, a job, etc.)
kerja = work, job

So:

lamaran kerja = job application

Structure: head noun lamaran + modifier kerja (what kind of application? a job/work application).

Compare:

lamaran beasiswa = scholarship application
lamaran visa = visa application

What is the difference between lamaran kerja and surat lamaran kerja?

lamaran kerja = job application (general: the whole application, which may include a letter, CV, forms, etc.)
surat lamaran kerja = job application letter (specifically the letter part)

So:

If the mentor trains students to write the letter, you might say surat lamaran kerja.
If you mean the skill of writing applications more generally, or just speak loosely, lamaran kerja is often used and understood as “job application letter” in everyday contexts.

In practice, many people do say menulis lamaran kerja when they specifically mean the letter, because it’s understood from context.

Why is there no preposition like untuk? Why not melatih keterampilan untuk menulis lamaran kerja?

Both are possible, but they sound slightly different:

melatih keterampilan menulis lamaran kerja
→ trains (their) job-application-writing skills
(compact phrase; menulis lamaran kerja directly describes the skill)
melatih keterampilan untuk menulis lamaran kerja
→ trains (their) skills in order to write job applications
(untuk = for, in order to; highlights purpose more explicitly)

In everyday language, structure [keterampilan + verb] is very common:

keterampilan menulis (writing skills)
keterampilan berbicara di depan umum (public speaking skills)

So the original sentence uses a very natural shorthand without untuk.

Could we say Mentor yang lain melatih menulis lamaran kerja? Is that wrong or just different?

Mentor yang lain melatih menulis lamaran kerja is grammatically possible, but the nuance changes:

melatih keterampilan menulis lamaran kerja
→ emphasizes the skills of writing job applications.
melatih menulis lamaran kerja
→ emphasizes the activity of writing job applications (training people to do that activity).

The version with keterampilan explicitly frames it as skill development. Without keterampilan, it sounds a bit more like “the mentor trains (them) to write job applications.” Both can be acceptable; the original just highlights “skills” more clearly.

Is there any tense marker in the sentence? How do we know if this is past, present, or future?

Indonesian verbs usually do not change form for tense. Melatih is the same for:

past: the other mentor trained …
present: the other mentor trains / is training …
future: the other mentor will train …

The tense is understood from context or added time words:

kemarin (yesterday) → past
sekarang (now) → present
besok (tomorrow) → future

For example:

Kemarin, mentor yang lain melatih keterampilan menulis lamaran kerja.
= Yesterday, the other mentor trained job-application-writing skills.

Without such markers, English translations choose a tense based on the most likely context.