Keputusan dewan itu penting.

Because Indonesian usually does not need a verb like is/am/are in simple present-tense statements.

So a pattern like:

• noun phrase + adjective

is enough to mean something is adjective.

Here, Keputusan dewan itu penting is a complete sentence, even without a separate word for is.

Compare:

• Rumah itu besar = the house is big
• Dia sakit = he/she is sick
• Makanan ini enak = this food is delicious

This is one of the biggest differences from English.

Because Indonesian usually puts the main noun first and the modifier after it.

So:

• keputusan = decision
• dewan = council / board

That gives:

• keputusan dewan = the council's decision / decision of the council

This is a very common Indonesian pattern. English often uses 's or of, but Indonesian often just places the nouns next to each other.

Other examples:

• buku siswa = the student's book
• kantor pemerintah = government office
• nama sekolah = school name

So keputusan dewan is normal Indonesian word order.

Itu literally often means that, but in real sentences it can also make a noun phrase sound specific or definite, something a bit like English the in some contexts.

So in a sentence like this, itu can help indicate that the speaker means a particular, known decision.

A key point: itu usually comes after the noun phrase it refers to.

Examples:

• rumah itu = that house / the house
• orang itu = that person
• keputusan dewan itu = that council decision / the council's decision / the decision of that council

So itu does not go before the noun like English that usually does.

Yes, it can be.

It may be understood in more than one way:

• keputusan [dewan itu] = the decision of that council
• [keputusan dewan] itu = that council decision

In real life, context usually makes the intended meaning clear.

That is why English translations may vary:

• the council's decision
• that council's decision
• that decision by the council

If you want to be clearer, Indonesian can be rephrased. For example:

• keputusan dewan tersebut = the decision of that council
• keputusan itu = that decision

So yes, this phrase can be structurally a little ambiguous.

Normally, no need.

In everyday Indonesian, adalah is not used the same way English uses is. With an adjective like penting, the most natural sentence is simply:

• Keputusan dewan itu penting

Using adalah here would sound stiff or overly formal:

• Keputusan dewan itu adalah penting

That is usually not the preferred everyday wording.

Adalah is more common in formal definitions or when linking one noun phrase to another, such as:

• Jakarta adalah ibu kota Indonesia = Jakarta is the capital of Indonesia

So for this sentence, leaving out adalah is the normal choice.

No. Penting stays the same.

Indonesian adjectives do not agree with nouns for:

• singular vs. plural
• gender
• person

So whether it is one decision or many decisions, penting does not change.

For example:

• Keputusan itu penting = that decision is important
• Keputusan-keputusan itu penting = those decisions are important

In both cases, penting stays exactly the same.

Keputusan is a noun meaning decision.

It is related to the root putus and to the verb memutuskan = to decide.

A useful pattern for learners is:

• memutuskan = to decide
• keputusan = decision

The ke- ... -an pattern often forms nouns, especially abstract nouns.

So if you already know the verb memutuskan, it is helpful to connect it to keputusan.

A rough English-friendly pronunciation is:

kuh-poo-too-sahn deh-wahn ee-too pen-ting

Broken into syllables:

• ke-pu-tu-san
• de-wan
• i-tu
• pen-ting

A few tips:

• The first e in keputusan is usually a weak vowel, like uh
• dewan has two syllables: de-wan
• ng in penting sounds like the ng in sing
• Indonesian stress is usually lighter and less dramatic than English stress

So try to keep it smooth and even, rather than strongly stressing one syllable the way English often does.