Ons heg die laailoper aan.

Because the full verb is aanheg, which is a separable verb in Afrikaans.

In a normal main clause, the conjugated part stays in the usual verb position, and the separable particle moves to the end:

• Ons heg die laailoper aan.

This is similar to Dutch and a bit like English phrasal verbs such as hook up or attach on, except Afrikaans does this much more systematically.

Compare:

• Main clause: Ons heg die laailoper aan.
• Infinitive: om die laailoper aan te heg
• Subordinate clause: dat ons die laailoper aanheg

So heg ... aan and aanheg are really the same verb in different sentence environments.

Ons means we.

One useful thing about Afrikaans is that verbs usually do not change much according to the subject. So the same verb form often works for different persons:

• Ek heg aan — I attach
• Jy heg aan — you attach
• Ons heg aan — we attach
• Hulle heg aan — they attach

So unlike English, where you get I attach but he attaches, Afrikaans is much simpler here.

Die is the definite article, meaning the.
’n is the indefinite article, meaning a/an.

So:

• die laailoper = the conveyor/loading belt/loader track
• ’n laailoper = a conveyor/loading belt/loader track

The sentence uses die because it is talking about a specific one, not just any one.

A nice feature of Afrikaans is that die is used for all genders and both singular/plural:

• die man — the man
• die vrou — the woman
• die kinders — the children

Yes, heg is a normal verb meaning attach, fasten, or affix, depending on context.

In this sentence, heg ... aan means something like:

• attach
• fasten
• connect

The exact English choice depends on what laailoper refers to in the wider context.

You may also see related forms such as:

• aanheg — to attach
• geheg — attached / affixed
• hegstuk — attachment, annex, fitting (depending on context)

Laailoper is a compound noun, which is very common in Afrikaans.

It is made up of:

• laai — load / loading
• loper — runner / belt / moving track, depending on context

Together, the compound refers to a specific piece of equipment. Afrikaans often combines words this way instead of using longer multi-word expressions.

This is very similar to English compounds such as:

• loading dock
• conveyor belt
• wheelbarrow
• fire engine

So even if the exact meaning has already been given to you, it is useful to notice that Afrikaans forms many technical nouns by simply joining smaller words.

Afrikaans main clauses usually follow a verb-second pattern. That means the finite verb comes early in the clause, usually in second position.

Here the structure is:

• Ons — subject
• heg — finite verb
• die laailoper — object
• aan — separated particle

So the sentence is perfectly normal Afrikaans word order.

If you moved things around too freely, it could sound unnatural or mean something slightly different. The standard neutral order here is:

• Ons heg die laailoper aan.

Afrikaans word order becomes especially important with separable verbs, because the particle often goes to the end in main clauses.

Yes. In a subordinate clause, the separable verb normally becomes one word again: aanheg.

For example:

• Ek weet dat ons die laailoper aanheg.
  = I know that we attach the laailoper.

Notice that aan is no longer separated from heg.

This is a very common pattern in Afrikaans:

• Main clause: Ons heg die laailoper aan.
• Subordinate clause: ... dat ons die laailoper aanheg.

This is one of the key things learners need to get used to with separable verbs.

You would usually say:

• om die laailoper aan te heg

This is the infinitive structure.

So you can compare:

• Ons heg die laailoper aan. — We attach the laailoper.
• Ons wil die laailoper aanheg. — We want to attach the laailoper.
• Dit is maklik om die laailoper aan te heg. — It is easy to attach the laailoper.

Notice the patterns:

• after a modal like wil, you often get aanheg
• with om ... te, you get aan te heg

Not really in a fully independent way. In this sentence, aan is functioning as the particle of the separable verb aanheg.

Historically and semantically, it is related to meanings like to, onto, or on, but in practice you should learn heg ... aan as a single verbal unit meaning attach/fasten to.

So it is better not to translate word by word as:

• ons = we
• heg = attach
• die laailoper = the laailoper
• aan = on

That can be misleading. It is better to think:

• heg ... aan = attach

A rough pronunciation guide is:

• Ons ≈ ons / awns
• heg ≈ like English heck but with a voiced g at the end for some speakers, or a softer guttural/fricative sound depending on accent
• die ≈ dee
• laailoper ≈ LIE-loh-per or LAAI-loh-per, depending on how you map the diphthong
• aan ≈ ahn

A rough full approximation could be:

• Ons heg die laailoper aan
  ≈ Ons heg dee LAAI-loh-per ahn

A few helpful pronunciation notes:

• aa is usually a long a sound.
• die is pronounced dee, not like English die.
• Afrikaans g is often a throat sound, though exact pronunciation varies by speaker and region.

In very informal speech, especially in technical workplaces, people may sometimes mix English and Afrikaans. But standard Afrikaans would use the Afrikaans verb:

• Ons heg die laailoper aan.

If you are learning proper Afrikaans, it is better to use heg ... aan or another standard verb that fits the context, rather than switching to English.

So for learning purposes, treat heg ... aan as the correct form here.