Learn Hardcore Malay: Sesetengah undang-undang kerja sangat ketat tentang umur yang paling rendah untuk bekerja. - Some labour laws are very strict about the lowest age for working.

Sesetengah undang-undang kerja ≈ Some labour laws (but not all).
Beberapa also means some / several, but it often implies a small number, more like a few.
Setengah by itself usually means half.

So:

sesetengah undang-undang = some of the laws
beberapa undang-undang = a few / several laws
setengah undang-undang would sound like half a law (odd in this context), so it isn’t used here.

In this sentence, sesetengah is the most natural choice to mean certain or some laws within a larger set.

Why is undang-undang written twice with a hyphen? Is it plural?

Undang-undang is a fixed word meaning law / laws; it is always written doubled like that.

Technically, the base word is undang, and undang-undang is a reduplicated noun, a common way in Malay to form plurals or make an abstract noun. But in practice:

You normally don’t say undang alone to mean a law.
Instead, undang-undang already means law / the law / laws, and plurality is often understood from context or from words like sesetengah.

So undang-undang here does represent multiple laws, but you should think of it as a standard dictionary word, not something you freely singularize to undang.

What does undang-undang kerja mean literally, and is it the same as labour laws?

Literally, undang-undang kerja is work laws:

undang-undang = laws
kerja = work

In Malay, a noun can follow another noun to describe it, so undang-undang kerja means laws related to work, i.e. employment / labour laws.

You might also see:

undang-undang buruh – more literally labour laws (with buruh = labour).
undang-undang pekerjaan – laws on employment.

All are understandable; undang-undang kerja is simple and clear, especially in general explanation.

There is no is / are in the Malay sentence. Where did the verb go?

Malay often drops the linking verb (the copula) when connecting a subject to an adjective or noun.

The English structure is:

Some labour laws *are very strict…*

In Malay, the structure is:

Sesetengah undang-undang kerja sangat ketat…

You can imagine an invisible adalah (is/are), but in normal speech and writing you simply omit it:

(Sesetengah undang-undang kerja) [adalah] sangat ketat…

So sangat ketat functions directly as the predicate are very strict without any extra verb.

What does sangat mean, and how is it different from terlalu or amat?

Sangat means very and is the most neutral, common intensifier for adjectives and some adverbs.

sangat ketat = very strict

Comparisons:

terlalu ketat = too strict (excessive, usually negative).
amat ketat = very strict, but sounds a bit more formal or emphatic than sangat.

In this sentence, sangat ketat simply describes a high degree of strictness, without judging it as too much.

What does ketat mean here? I thought it meant tight.

Literally, ketat does mean tight, as in tight clothes:

Seluar ini terlalu ketat. = These pants are too tight.

By extension, it also means strict / rigid when applied to rules, systems, or control:

peraturan yang ketat = strict regulations
kawalan yang ketat = tight/strict control

So undang-undang kerja sangat ketat = the labour laws are very strict. It is a natural metaphor in Malay, similar to how English uses tight control or strict rules.

What is the function of tentang, and can I replace it with mengenai or berkenaan?

Tentang means about / concerning / regarding:

ketat tentang umur… = strict about the age…

You can often replace tentang with:

mengenai
berkenaan (dengan)

They all mean roughly about. Differences:

tentang – very common and neutral.
mengenai – slightly more formal.
berkenaan (dengan) – more formal / official-sounding.

So you could say:

sangat ketat mengenai umur…
sangat ketat berkenaan umur…

All are acceptable; in everyday use, tentang is perfectly natural.

Can you break down umur yang paling rendah untuk bekerja grammatically?

Yes. The phrase consists of:

umur = age
yang = a marker introducing a descriptive clause (similar to that / which or that is)
paling rendah = the lowest / the most low
untuk bekerja = to work / for working

So the structure is roughly:

umur [yang paling rendah untuk bekerja]
= the age [that is the lowest for (being allowed to) work]
= the minimum age for working.

Yang links umur to the description paling rendah untuk bekerja, turning that description into a clause that qualifies umur.

Is yang really necessary before paling rendah? Could I say umur paling rendah untuk bekerja?

You can say umur paling rendah untuk bekerja, and many native speakers would still find it acceptable and understandable. However:

In careful or formal Malay, yang is commonly used before superlatives like paling rendah, paling tinggi, etc., to link them clearly to the noun.
umur yang paling rendah sounds slightly more complete and standard, especially in a sentence that resembles legal or formal language.

So both can appear in real usage, but umur yang paling rendah is the safer, more textbook-like form.

Could I just say umur minimum untuk bekerja instead of umur yang paling rendah untuk bekerja?

Yes. Umur minimum untuk bekerja is shorter and also very natural:

umur minimum = minimum age

So you could say:

Sesetengah undang-undang kerja sangat ketat tentang umur minimum untuk bekerja.

Both expressions mean the same thing. Umur minimum sounds a bit more technical/formal (and closer to English minimum age), while umur yang paling rendah untuk bekerja is more descriptive.

What does untuk bekerja do here? Is it like an infinitive?

Yes. Untuk + verb is a common way to express to do something / for doing something.

bekerja = to work (base verb)
untuk bekerja = in order to work / for (the purpose of) working

In umur yang paling rendah untuk bekerja, untuk bekerja explains the purpose related to the age:

the lowest age for working.

Other examples:

lesen untuk memandu = license to drive
alat untuk memasak = tools for cooking

So you can think of untuk bekerja as the equivalent of an infinitive clause to work / for working.

Why is it paling rendah and not terendah?

Both paling rendah and terendah can express a superlative the lowest.

paling rendah = the most low / lowest
terendah = the lowest

Subtle points:

paling + adjective is very common and works with almost any adjective.
ter- superlatives like terendah, tertinggi are also correct; they can sound a bit more formal or technical depending on context.

In this sentence, you could say:

umur yang paling rendah untuk bekerja
or
umur yang terendah untuk bekerja

Both are grammatically fine; paling rendah is just the more neutral-sounding choice here.

Could we move sangat ketat to the end, like Sesetengah undang-undang kerja tentang umur yang paling rendah untuk bekerja sangat ketat?

Yes, that word order is still grammatical and understandable:

Sesetengah undang-undang kerja tentang umur yang paling rendah untuk bekerja sangat ketat.

In this version, the focus feels slightly more on the rules about the minimum age, then we comment sangat ketat at the end.

The original order:

Sesetengah undang-undang kerja sangat ketat tentang umur yang paling rendah untuk bekerja.

puts sangat ketat closer to undang-undang kerja, which is a very natural pattern in Malay:
[subject] + [adjective] + [further explanation].

Both are possible; the original sentence is a bit smoother and more typical.

Is this sentence more formal or casual, and would it sound natural in everyday speech?

The sentence is neutral to slightly formal, mainly because it talks about laws and minimum working age, which are formal topics. The vocabulary itself (sesetengah, undang-undang, sangat ketat, tentang, umur, paling rendah, untuk bekerja) is standard, not slangy.

In everyday conversation you might still say it this way, or you might shorten it, for example:

Ada undang-undang kerja yang sangat ketat pasal umur minimum kerja.

But as given, the sentence is natural, clear, and appropriate for general explanation, teaching, or writing.