Doktor kata lengan saya perlu direhatkan dua hari kerana saya tersalah angkat kotak berat.

Kata is very common in everyday Malay to mean said / says. In conversation, doktor kata ... sounds natural and idiomatic.

• doktor kata ... = the doctor said ...
• doktor berkata ... = the doctor said ... / the doctor spoke ...

Berkata is more formal and a little more literary. In normal speech, people often prefer kata.

So this sentence sounds like natural spoken or informal written Malay.

In Malay, the word bahawa can mean that in reported speech, but it is often omitted.

So these are both possible:

• Doktor kata lengan saya perlu direhatkan ...
• Doktor kata bahawa lengan saya perlu direhatkan ...

The version without bahawa is more common in everyday speech and still completely clear.

In Malay, possessors usually come after the noun.

• lengan saya = my arm
• rumah saya = my house
• kawan saya = my friend

So the pattern is:

• noun + saya/awak/dia/kami/etc.

That is the normal way to show possession in Malay.

Perlu means need to / needs to / necessary to.

Direhatkan comes from rehat (rest) and has the passive form di-...-kan. Here it means something like:

• to be rested
• to be given rest
• to be kept at rest

So:

• lengan saya perlu direhatkan = my arm needs to be rested

This is a very natural way to talk about an injured body part in Malay.

This is a useful word to break down:

• rehat = rest
• merehatkan = to rest something / to give something rest
• direhatkan = to be rested

So:

• Saya merehatkan lengan saya = I rest my arm / I am resting my arm
• Lengan saya direhatkan = My arm is rested / needs to be rested

The di- prefix is a common marker for the passive in Malay.

The -kan ending often gives a causative or transitive sense, so merehatkan/direhatkan is not just to rest, but more like to let something rest or to give something a rest.

In Malay, duration can often be expressed directly with the time phrase, without needing an extra word.

So:

• direhatkan dua hari = rested for two days

This is normal Malay.

You can also say:

• direhatkan selama dua hari

Here selama explicitly marks duration, like for in English. Both are correct, but the version without selama is common and natural.

Kerana means because.

So:

• ... kerana saya tersalah angkat kotak berat = ... because I mistakenly lifted a heavy box

Other common alternatives are:

• sebab = because (very common, more conversational)
• oleh sebab = because of / due to (more formal)

So in everyday speech, many speakers would also say:

• Doktor kata lengan saya perlu direhatkan dua hari sebab saya tersalah angkat kotak berat.

Tersalah shows that something was done mistakenly, wrongly, or by accident.

So:

• tersalah angkat = lifted wrongly / lifted by mistake / used the wrong lifting method

In this sentence, it suggests the speaker injured their arm because they lifted the heavy box incorrectly or made a mistake when lifting it.

This is a helpful pattern:

• salah = wrong
• tersalah = accidentally did wrongly / made a mistake in doing something

Compare:

• Saya salah cakap. = I said the wrong thing.
• Saya tersalah cakap. = I misspoke / I said it wrongly by mistake.

So ter- here often adds the idea of an unintended mistake.

In Malay, adjectives usually come after the noun.

• kotak berat = heavy box
• rumah besar = big house
• baju merah = red shirt

So the normal order is:

• noun + adjective

That is why kotak berat is correct.

Each saya has a different role:

• lengan saya = my arm
• kerana saya tersalah ... = because I mistakenly ...

So the first saya is a possessor, and the second saya is the subject of the clause after kerana.

Malay often repeats pronouns where English might also repeat them. Leaving out the second saya here would make the sentence incomplete or unclear.

Yes, lengan can mean arm, and in some contexts it can also relate to sleeve.

But in this sentence, because of:

• doktor
• perlu direhatkan
• tersalah angkat kotak berat

the meaning is clearly arm, not sleeve.

So here:

• lengan saya = my arm

It sounds mostly natural and conversational, especially because of:

• doktor kata instead of the more formal doktor berkata
• omission of bahawa
• direct time expression dua hari

It is still perfectly correct and easy to understand. A more formal version might be:

• Doktor berkata bahawa lengan saya perlu direhatkan selama dua hari kerana saya tersalah mengangkat kotak berat.

Notice the more formal choices:

• berkata
• bahawa
• selama
• mengangkat

But the original sentence is very natural for everyday Malay.