Learn Hardcore Indonesian: Insinyur yang saya kenal sering bekerja sama dengan arsitek dalam satu proyek. - An engineer I know often works together with an architect on one project.

Without yang, Insinyur saya kenal is not natural Indonesian as a relative-clause structure. Yang is needed to link the noun to the descriptive clause.

Compare:

Insinyur yang saya kenal = the engineer that I know
Insinyur saya = my engineer (possessive: my
- engineer)

If you drop yang, a native speaker will either find it wrong or try to interpret insinyur saya as a phrase meaning my engineer, and then kenal becomes an extra verb that doesn’t fit well.

So for “the engineer that I know”, you really need yang:

✅ Insinyur yang saya kenal
❌ Insinyur saya kenal (ungrammatical in this sense)

How do we know that saya kenal means “I know (the engineer)” and not “knows me”?

Word order inside the relative clause matters.

Insinyur yang saya kenal
- saya = subject
- kenal = verb
- (object is the head noun insinyur)
  → “the engineer that I know”

If you want “the engineer who knows me”, you change the order:

Insinyur yang kenal saya
- (insinyur) = subject of kenal
- kenal = verb
- saya = object
  → “the engineer who knows me”

So:

yang saya kenal = that I know
yang kenal saya = who knows me

What’s the difference between kenal and mengenal here? Could I say Insinyur yang saya mengenal?

The base meaning is similar (both relate to know someone), but usage and grammar differ:

kenal
- Very common in everyday speech
- Often used as kenal + object
- Example: Saya kenal dia. (I know him/her.)
mengenal
- More formal or literary
- Also used as mengenal + object
- Example: Saya mengenal dia. (I know him/her.)

In this particular structure:

✅ Insinyur yang saya kenal (very natural)
❌ Insinyur yang saya mengenal (sounds wrong/unnatural)

With mengenal, you would normally restructure:

Insinyur yang saya mengenalnya (still odd)
Better: Insinyur yang saya telah mengenal dia sejak lama (still clunky)

For this simple relative clause, kenal is the idiomatic choice. If you want to use mengenal, do it in a full, less compact sentence:

Saya mengenal insinyur itu. (I know that engineer.)

Is Insinyur here singular or plural? Does it mean “engineer” or “engineers”?

By default, Indonesian nouns do not mark singular/plural. Insinyur can mean:

an engineer / the engineer
engineers / the engineers

Context decides.

If you want to make plurality explicit:

Para insinyur = the engineers (group, plural)
Banyak insinyur = many engineers
Insinyur-insinyur = engineers (reduplication; less common in this context)

So:

Insinyur yang saya kenal…
→ could be “The engineer that I know…” or “The engineers that I know…”, depending on context.

If you want to be clearly plural:

Para insinyur yang saya kenal sering bekerja sama…
= The engineers that I know often work together…

What exactly does bekerja sama mean, and why is it two words? Can I write bekerjasama?

Bekerja sama is a verb phrase meaning to cooperate / to collaborate / to work together.

Morphology:

bekerja = to work
sama = together / same

So literally “to work together”.

Regarding spelling:

Current standard (per official spelling guidelines): bekerja sama (two words)
You may still see bekerjasama or bekerja-sama in older texts, but bekerja sama is the recommended modern form.

All of these are understood, but when you write, prefer:

✅ sering bekerja sama dengan arsitek

Where does sering usually go? Could I say Sering insinyur yang saya kenal bekerja sama…?

In this sentence, sering (often) is placed right before the verb phrase it modifies:

Insinyur yang saya kenal sering bekerja sama…
→ sering modifies bekerja sama.

This position (before the verb) is the most common and neutral for adverbs like sering.

Other options:

Sering, insinyur yang saya kenal bekerja sama…
- Possible if sering is used as a sentence-level adverb for emphasis, often with a pause/comma.
- Feels more stylistic, like “Often, the engineer(s) I know collaborate…”.
Insinyur yang saya kenal bekerja sama sering…
- This sounds odd and is not natural.

For your level, the safe pattern is:

[Subject] + sering + [verb phrase]
Insinyur yang saya kenal sering bekerja sama…

Does dengan arsitek mean “with the architect” or “with architects in general”? Should I say seorang arsitek or para arsitek?

Again, Indonesian doesn’t mark number by default, so arsitek alone can be:

an architect / the architect
architects / the architects

dengan arsitek can mean:

with an architect
with (an) architect(s)
with architects in general

To make it more specific:

dengan seorang arsitek = with an architect (one person, singular, non-specific)
dengan para arsitek = with (the) architects (plural group)
dengan banyak arsitek = with many architects

In many real contexts, dengan arsitek is understood as “with architects” in general, especially if we’re talking about typical work patterns.

Why is it dalam satu proyek and not di satu proyek or pada satu proyek? What’s the nuance?

All three prepositions (dalam, di, pada) can appear with proyek, but they have different common uses:

dalam satu proyek
- Literally: within one project
- Feels a bit more abstract or “inside the scope of a project”.
- Very natural in written and semi-formal language.
di satu proyek
- Literally: at / in one project
- More physical/location-like; often used for a place or assignment:
  - Saya bekerja di satu proyek di Jakarta. (I work on a project in Jakarta.)
pada satu proyek
- Slightly more formal; overlaps with di in meaning here.
- Common in formal writing: bekerja pada proyek X.

In your sentence, dalam satu proyek emphasizes cooperation within the same project (the same project framework) rather than simply being assigned on a project.

You could also say dalam sebuah proyek; satu and sebuah here both function like “a / one”, with satu more explicitly numeric.

Can I just say Insinyur sering bekerja sama dengan arsitek dalam satu proyek and drop yang saya kenal?

Yes, grammatically you can, but the meaning changes:

Insinyur yang saya kenal sering bekerja sama…
→ Narrow group: “The engineer(s) that I know often collaborate…”
Insinyur sering bekerja sama…
→ General statement: “Engineers often collaborate…” (engineers in general, not specifically the ones you know)

So yang saya kenal is a restrictive relative clause: it restricts the sentence to engineers that you know. Dropping it makes the statement about engineers as a broader category.