Akar gigi itu sakit.

• akar = root
• gigi = tooth / teeth
• itu = that, or often the when pointing to a specific thing already known in context
• sakit = sick, ill, painful, hurting

So the structure is basically:

akar gigi itu + sakit
that/the tooth root + hurts / is painful

In Indonesian, it is very normal for a sentence like this to have no separate word for is.

Indonesian often leaves out the equivalent of is/am/are in simple sentences.

So:

• Akar gigi itu sakit = That tooth root is painful / The tooth root hurts

This is completely normal Indonesian.
You do not need a word like is here.

The same pattern appears in many basic sentences:

• Rumah itu besar = That house is big
• Dia sakit = He/She is sick

It can feel like either one, depending on context.

Literally, itu often means that. But in many natural sentences, it also works a lot like the, marking something specific that both speaker and listener can identify.

So akar gigi itu could mean:

• that tooth root
• the tooth root

In real usage, the best English translation depends on the situation.

In Indonesian noun phrases, the main noun usually comes first, and the word that describes or specifies it comes after.

So:

• akar gigi = tooth root literally root of tooth
• sakit gigi = toothache
• dokter gigi = dentist literally tooth doctor

The pattern is often:

main thing + specifier

So akar gigi is natural Indonesian word order.

By itself, akar gigi is quite general and can mean tooth root or root of a tooth. Indonesian often does not force you to mark definiteness the way English does.

When you add itu, it becomes specific:

• akar gigi itu = that/the tooth root

So the sentence is talking about a particular tooth root, not just tooth roots in general.

Here it means painful / hurts.

Sakit has a broad meaning range. It can describe:

• a person being ill: Saya sakit = I’m sick
• a body part hurting: Tangan saya sakit = My hand hurts
• something being painful: Suntikan itu sakit = That injection is painful

In Akar gigi itu sakit, it refers to pain, not illness in the general sense.

Yes, it is understandable and acceptable.

That said, in everyday conversation, Indonesian speakers often talk about the whole tooth or use a possessive ending when referring to body parts more naturally. For example:

• Gigi itu sakit = That tooth hurts
• Akar giginya sakit = The root of the tooth hurts / its tooth root hurts

Your sentence is still fine, especially if the tooth root has already been identified in the conversation.

Indonesian often leaves out information that is obvious from context.

So Akar gigi itu sakit just says that a specific tooth root hurts. It does not explicitly say whose tooth it is.

If you want to be specific, you can add that information:

• Akar gigi saya sakit = My tooth root hurts
• Akar giginya sakit = His/Her tooth root hurts or the tooth root hurts, depending on context

Indonesian is often less explicit than English about possession unless it matters.

Normally, itu comes after the noun phrase it modifies.

So:

• akar gigi itu = correct

This is the normal order for that/the tooth root.

Putting itu in a different place would usually change the structure or sound unnatural.

A useful pattern to remember is:

noun + itu = that noun / the noun

Examples:

• rumah itu = that house
• orang itu = that person
• gigi itu = that tooth

It is understood as singular here because of the meaning of the phrase.

Gigi can mean tooth or teeth depending on context. Indonesian nouns usually do not change form for singular vs. plural.

But in akar gigi itu, the intended meaning is clearly the root of that tooth or that tooth root, not multiple teeth.

Context usually tells you whether a noun is singular or plural.

A simple approximation is:

AH-kar GEE-jee EE-too SAH-keet

A few notes:

• g in gigi is always a hard g, like in go
• c is not present here, but in Indonesian it is usually like ch
• the r in akar is often lightly rolled or tapped
• stress in Indonesian is usually not as strong or important as in English

So just saying it clearly and evenly will usually sound fine.