Dia menggaruk lehernya karena gatal.

Yes. Dia can mean either he or she. Indonesian does not usually mark gender in third-person singular pronouns.

So Dia menggaruk lehernya karena gatal could mean:

• He scratched his neck because it was itchy
• She scratched her neck because it was itchy

You only know the gender from context.

Garuk is the base word, meaning scratch.

Menggaruk is the active verb form, built with the prefix meng-. In ordinary statements, Indonesian often uses this meN- form for active verbs.

So:

• garuk = the root/base
• menggaruk = to scratch / scratches / scratched depending on context

In a full sentence, menggaruk sounds natural and standard:

• Dia menggaruk lehernya = He/She scratched his/her neck

Using just garuk would sound more like a command or a less complete form in many contexts.

Here -nya means his/her.

So:

• leher = neck
• lehernya = his neck / her neck

In this sentence, lehernya most naturally refers back to dia, so it means his/her neck.

But -nya is very flexible in Indonesian. Depending on context, it can also mean things like:

• his/her
• its
• the (in some contexts)
• a context-based third-person reference

Here, though, the simplest reading is his/her neck.

Because Indonesian often does not need a verb like to be in sentences of description.

So:

• gatal = itchy
• karena gatal = because itchy / because it was itchy

This is completely normal in Indonesian. The idea of was/is is understood from context.

That is why karena gatal sounds natural, even though in English we need because it was itchy.

In this sentence, the most natural interpretation is that the neck was itchy, so the person scratched their neck.

Even though Indonesian does not explicitly repeat lehernya after karena gatal, the meaning is understood from context:

• Dia menggaruk lehernya karena gatal
  = He/She scratched his/her neck because it was itchy

The itchy part is understood to relate to the neck.

In some situations, gatal can describe a person generally, but here the action of scratching the neck strongly points to the neck being itchy.

Yes, in theory it could, because -nya does not always have to refer to the subject.

So grammatically, Dia menggaruk lehernya could sometimes mean:

• He/She scratched his/her own neck
• He/She scratched someone else’s neck

But without extra context, most learners should understand it as his/her own neck, because that is the most natural reading here.

If Indonesian wants to be very clear, it can add more detail, for example:

• Dia menggaruk lehernya sendiri = He/She scratched his/her own neck
• Dia menggaruk leher anaknya = He/She scratched his/her child’s neck

It is usually best to think of gatal as an adjective/state word, meaning itchy.

Examples:

• Kulit saya gatal. = My skin is itchy.
• Tangannya gatal. = His/Her hand is itchy.

But in Indonesian, words describing states often behave more flexibly than in English. That is why gatal can function naturally as the main predicate without needing is.

So for a learner, the safest understanding here is:

• gatal = itchy

This sentence follows a very common Indonesian order:

• Dia = subject
• menggaruk = verb
• lehernya = object
• karena gatal = reason

So the structure is basically:

Subject + Verb + Object + Reason

This is very natural in Indonesian.

You can sometimes move the reason phrase for emphasis, for example:

• Karena gatal, dia menggaruk lehernya.

That means the same thing, but it puts more focus on the reason first.

Yes, that is possible. Sebab can also mean because.

But karena is generally the more common everyday choice in sentences like this.

So:

• karena gatal = because it was itchy
• sebab gatal = because it was itchy

Both are understandable, but karena usually sounds more natural in ordinary conversation.

No. Indonesian verbs usually do not change form for tense the way English verbs do.

So menggaruk by itself can mean:

• scratch
• scratches
• scratched
• is scratching

The time is normally understood from context.

That means Dia menggaruk lehernya karena gatal could be interpreted as:

• He/She scratched his/her neck because it was itchy
• He/She scratches his/her neck because it is itchy
• He/She is scratching his/her neck because it is itchy

If the surrounding context is past, present, or habitual, that will decide the best English translation.

Yes, it is natural and normal Indonesian.

It is short, clear, and idiomatic. Indonesian often leaves some things implicit when they are obvious from context, especially:

• the subject’s gender
• tense
• the understood was/is
• the fact that gatal refers to the neck

So this sentence is a good example of how Indonesian can be more compact than English while still sounding completely natural.