Jy moet nie afval weggooi wat kompos kan word nie.

Afrikaans usually uses double negation.

So in Jy moet nie afval weggooi wat kompos kan word nie, the pattern is:

• nie after the verb phrase begins the negation
• the final nie closes it

A very rough structure is:

• Jy moet nie ... nie = You must/should not ...

This is one of the most important patterns in Afrikaans. English uses only one not, but Afrikaans normally uses two nies in sentences like this.

Moet often means must, but in real usage it can also sound like should, depending on context and tone.

So here it can suggest:

• must not
• should not

If the sentence is giving advice, English may prefer should not.
If it is a firm rule or instruction, must not may fit better.

So the grammar word is moet, but the best English equivalent depends on how strong the speaker wants to sound.

Here afval is a noun meaning:

• waste
• trash
• refuse

So in this sentence, afval refers to waste material.

This can be confusing because afval can also be a verb in other contexts, with meanings like lose weight or fall off. But here, because of the sentence structure, it is clearly the noun waste.

Weggooi is an infinitive form meaning to throw away.

Afrikaans has many verbs with a main part plus another element like weg-, and their spelling/position can change depending on the sentence.

Here, after the modal verb moet, the infinitive stays together:

• moet ... weggooi

Compare that with a main clause where the verb is conjugated:

• Ek gooi dit weg. = I throw it away.

So:

• gooi ... weg when the verb is finite in the clause
• weggooi when it appears as an infinitive after a modal like moet or kan

That part is a relative clause describing afval.

• wat = that / which
• wat kompos kan word = that can become compost / that can be composted

So the clause tells you which kind of waste is meant: not all waste, but specifically waste that can turn into compost.

In English, we do the same thing:

• waste that can become compost

In Afrikaans, wat is the normal relative pronoun used in many situations where English uses that, which, or sometimes who.

Here it links afval with the description that follows:

• afval wat kompos kan word
• waste that can become compost

So wat is doing the job of introducing the relative clause.

Yes — word often means become, and that is the main idea here.

So:

• kompos kan word = can become compost

But word is also used in passive constructions in Afrikaans, so learners often notice it in both roles.

In this sentence, the most natural understanding is become:

• waste that can become compost

Depending on the broader context, English might also express the idea as:

• waste that can be composted

That is slightly freer in translation, but it matches the practical meaning well.

Kan means can / be able to.

So:

• word = become
• kan word = can become

The speaker is not saying the waste definitely becomes compost every time, only that it has the possibility of becoming compost.

That is why kan is included.

This is because the phrase is inside a subordinate clause introduced by wat.

In Afrikaans subordinate clauses, the verbs usually move toward the end. With a modal plus infinitive, you often get:

• ... wat kompos kan word

So the order is:

• object/complement: kompos
• modal: kan
• infinitive: word

This is normal Afrikaans subordinate-clause word order.

Because afval is being used as a mass noun, like waste in English.

Compare:

• Throw away waste
  not necessarily
• Throw away a waste

So Afrikaans does not need 'n here. The sentence is talking about waste in general, not one specific piece or item.

Yes, that would be a very natural alternative.

• komposteerbare afval = compostable waste

So:

• Jy moet nie komposteerbare afval weggooi nie means roughly
• You shouldn’t throw away compostable waste

The original sentence with wat kompos kan word is a bit more descriptive and explicit, while komposteerbare is more compact and adjective-based. Both are understandable and natural.