Learn Hardcore Malay: Kadang-kadang telinga saya sakit bila muzik terlalu kuat. - Sometimes my ears hurt when the music is too loud.

The standard written form is kadang-kadang (with the hyphen).
In informal writing you may see kadang kadang (space, no hyphen), but for correct standard Malay, keep the hyphen.
It has the same feel as English “sometimes / occasionally”, not “rarely” or “often”.

Why is it telinga saya and not saya telinga for “my ear(s)”?

In Malay, possessives usually follow the noun:

telinga = ear
saya = I / me / my
telinga saya = my ear / my ears

So the pattern is noun + possessor:

rumah saya = my house
buku saya = my book
telinga saya = my ear(s)

Saya telinga would be ungrammatical in this context.

Does telinga mean “ear” or “ears”? How do I show plural?

Telinga by itself can mean “ear” or “ears”, depending on context. Malay often doesn’t mark plural.

If you really want to be explicit:

sebelah telinga = one ear
dua belah telinga = two ears / both ears
kedua-dua telinga saya = both my ears

In your sentence, telinga saya can naturally be understood as “my ears” because that’s how we usually talk about this kind of pain.

Is sakit a verb (“hurt”) or an adjective (“painful / sore / sick”) here?

In Malay, sakit can function like both a verb and an adjective, depending on context:

As an adjective: telinga saya sakit ≈ “my ear(s) are sore / painful.”
As a verb-like predicate: the same sentence is often translated as “my ear(s) hurt.”

Malay doesn’t strictly separate “is painful” vs “hurts” the way English does; sakit simply describes the state of having pain or being ill.

Could I say telinga saya rasa sakit instead of telinga saya sakit?

Yes:

telinga saya sakit = my ear(s) hurt / my ear(s) are sore.
telinga saya rasa sakit = my ear(s) feel painful.

Rasa means “to feel” (here, physically).
Both are natural, but telinga saya sakit is shorter and very common in everyday speech.

What is the function of bila in this sentence? Is it the same as “when” in English?

Yes. Here bila works as a conjunction meaning “when”:

… sakit bila muzik terlalu kuat = “… hurt when the music is too loud.”

You can also use bila to ask questions:

Bila kamu datang? = When are you coming?

In more formal Malay, you might see apabila or ketika used in place of bila in this kind of “when”-clause.

Can I move the bila… part to the front, like in English “When the music is too loud, my ears hurt”?

Yes, that’s completely acceptable:

Bila muzik terlalu kuat, telinga saya sakit.
Kadang-kadang bila muzik terlalu kuat, telinga saya sakit.

Malay allows both orders:

Main clause first: Telinga saya sakit bila muzik terlalu kuat.
“When”-clause first: Bila muzik terlalu kuat, telinga saya sakit.

The meaning is the same; it’s just a different flow.

What does terlalu add to kuat? What’s the difference between kuat and terlalu kuat?

kuat = strong / loud (depending on context)
terlalu kuat = too loud (excessively loud)

So:

muzik kuat = the music is loud.
muzik terlalu kuat = the music is too loud (more than is comfortable / acceptable).

In your sentence, terlalu is important because it explains why the ears hurt: the music is excessively loud.

Is kuat always about sound, or can it mean other things?

Kuat is a general word meaning “strong”, and by extension “loud” for sounds:

angin kuat = strong wind
orang yang kuat = a strong person
suara kuat = loud voice
muzik kuat = loud music

So the idea is strength or intensity, and for sound that becomes “loud”.

Why is it muzik with a k, not musik?

In Malay (Bahasa Melayu), the standard spelling is muzik.
In Indonesian (Bahasa Indonesia), the word is usually spelled musik.

So:

Malay: muzik
Indonesian: musik

They mean the same thing; the final consonant reflects different standard spelling systems.

Could I drop saya and just say telinga sakit bila muzik terlalu kuat?

Yes, you can say:

Telinga sakit bila muzik terlalu kuat.

This would normally be understood as “(my) ears hurt when the music is too loud,” especially if you are talking about yourself.

However, telinga saya sakit is slightly clearer that you’re talking about your ears, not people’s ears in general. In normal conversation about your own condition, both are acceptable.

Is kadang-kadang supposed to go at the beginning of the sentence, or can it move around?

Kadang-kadang is quite flexible in position:

Kadang-kadang telinga saya sakit bila muzik terlalu kuat.
Telinga saya kadang-kadang sakit bila muzik terlalu kuat.
Telinga saya sakit kadang-kadang bila muzik terlalu kuat. (less common, but possible in speech)

Most natural are the first two. Putting kadang-kadang right at the start (as in your sentence) is very common and sounds natural.