Debu di selimut membuat tangan saya gatal, jadi saya terus menggaruknya.

No. These are two different things.

• di written as a separate word is a preposition meaning in / on / at
• di- attached to a verb is the passive prefix

So:

• debu di selimut = dust on/in the blanket
• digaruk = is scratched

A useful rule: if di is separate, it is usually a location word; if it is attached to a verb, it is usually passive.

It can suggest either, depending on context. Indonesian di is more general than English in/on/at.

So debu di selimut can mean:

• dust on the blanket
• dust in the blanket / in its fabric

English forces you to choose more precisely, but Indonesian often does not.

In Indonesian, possessors normally come after the noun.

• tangan saya = my hand / my hands
• rumah saya = my house
• buku John = John's book

So the pattern is:

noun + possessor

not

possessor + noun

like in English.

It can mean either. Indonesian nouns usually do not have to show singular vs. plural.

So tangan saya may mean:

• my hand
• my hands

The context decides. If you want to be extra specific, you could say:

• kedua tangan saya = both my hands

Indonesian often leaves out the verb to be in simple present descriptions.

So:

• tangan saya gatal literally looks like my hand(s) itchy
• but it naturally means my hand is itchy or my hands are itchy

This is very common with adjectives:

• saya lelah = I am tired
• rumah itu besar = that house is big

So gatal works like an adjective here, and no separate is/are is needed.

Membuat literally means to make, and it is often used for cause + result.

Here the pattern is:

X membuat Y + adjective

So:

• Debu di selimut membuat tangan saya gatal
• literally: The dust on/in the blanket made my hand(s) itchy

This is a very common structure in Indonesian.

Other examples:

• Asap membuat mata saya perih = Smoke makes my eyes sting
• Cuaca panas membuat saya lelah = Hot weather makes me tired

Here jadi means so or therefore.

It connects the first clause to the result:

• dust made the hands itchy
• jadi = so
• I kept scratching them

In everyday Indonesian, jadi is a very common and natural way to show a result. In more formal writing, you might also see words like sehingga or maka.

Here terus means continuously, kept on, or continued to.

So:

• saya terus menggaruknya = I kept scratching it/them

This is a common use of terus before a verb.

Compare:

• Dia terus berbicara = He kept talking
• Anak itu terus menangis = The child kept crying

Be careful: terus can also mean straight ahead in other contexts, so its exact meaning depends on the sentence.

Here -nya most naturally refers to tangan saya or the itchy body part.

So menggaruknya means:

• scratch it
• or in natural English here, probably scratch them

Even though English may need them, Indonesian can still use -nya, because Indonesian nouns often do not mark plural clearly.

You could also say the full noun instead:

• saya terus menggaruk tangan saya

But using -nya sounds natural and avoids repetition.

Garuk is the root word, meaning scratch.
Menggaruk is the active verb form, made with the meN- prefix.

So:

• garuk = root
• menggaruk = to scratch

In standard Indonesian, the active verb usually uses this prefix. The bare root garuk is more likely in commands or informal speech, such as:

• Garuk saja = Just scratch it
• Jangan digaruk = Don't scratch it

The active prefix is often described as meN-, and its shape changes depending on the first sound of the root.

Because garuk starts with g, the form becomes meng-:

• meN- + garuk → menggaruk

This kind of change is very common in Indonesian. For example:

• meN- + baca → membaca
• meN- + tulis → menulis
• meN- + sapu → menyapu

So meng- is just the correct form of the prefix before a root like garuk.

It is repeated because the sentence has different parts with different roles, and Indonesian often repeats pronouns for clarity.

In this sentence:

• Debu di selimut = subject of the first clause
• tangan saya = object/complement inside that clause
• saya = subject of the second clause

So the second saya is not redundant; it clearly shows who is doing the scratching.

Could Indonesian omit it in some contexts? Sometimes yes, especially in casual speech if the subject is obvious. But in a complete, clear sentence, repeating saya is perfectly normal.