Dokumentari ini menarik.

• dokumentari = documentary
• ini = this
• menarik = interesting

So the sentence literally lines up as documentary this interesting, but in natural English it means This documentary is interesting.

In Malay, demonstratives like ini (this) and itu (that) usually come after the noun.

So:

• dokumentari ini = this documentary
• dokumentari itu = that documentary

This is different from English, where this comes before the noun.

Malay often leaves out the verb to be in simple sentences like this.

So instead of saying something equivalent to This documentary is interesting, Malay simply says:

• Dokumentari ini menarik

This is completely normal and natural.
You do not need a separate word for is here.

In Malay, adjectives usually come after the noun they describe.

So:

• dokumentari menarik = interesting documentary

In your sentence, menarik comes after dokumentari ini, giving:

• Dokumentari ini menarik = This documentary is interesting

That is normal Malay word order.

Menarik most commonly means interesting or attractive/appealing, depending on context.

For example:

• cerita yang menarik = an interesting story
• tempat yang menarik = an attractive / interesting place

So in Dokumentari ini menarik, the meaning is clearly interesting.

It is possible in some contexts, but Dokumentari ini menarik is the most standard and natural way to say This documentary is interesting.

Why?

• dokumentari ini is the normal noun phrase for this documentary
• then menarik describes it

So learners should treat Dokumentari ini menarik as the safest pattern.

You just replace ini with itu:

• Dokumentari itu menarik.

So:

• ini = this
• itu = that

Add sangat before the adjective:

• Dokumentari ini sangat menarik.

Here:

• sangat = very
• menarik = interesting

So sangat menarik = very interesting.

Use tidak before the adjective:

• Dokumentari ini tidak menarik.

Here:

• tidak = not

Malay commonly uses tidak to negate adjectives and verbs.

Yes. Dokumentari is a loanword, ultimately from documentary. Malay spelling often adapts borrowed words to fit Malay pronunciation and spelling patterns.

That is why it looks similar to English, but not exactly the same.

A simple English-friendly approximation is:

• doh-koo-men-TA-ree ee-nee muh-NA-rik

A few tips:

• r is usually tapped or rolled lightly
• Malay vowels are generally pronounced clearly
• stress is less heavy than in English

You do not need perfect pronunciation right away; clear syllables are more important.

It is neutral and natural. It works well in both speech and writing.

• In conversation: perfectly normal
• In writing: also perfectly acceptable

So Dokumentari ini menarik is a very useful model sentence for beginners.