Die kinders is aan die wag vir hul beurt om die kos te proe.

Because die is the normal definite article in Afrikaans for all genders and for both singular and plural nouns.

So:

• die kind = the child
• die kinders = the children
• die kos = the food

Unlike some other languages, Afrikaans does not change the definite article for gender or number.

This is a way of showing that the action is in progress.

• is = a form of wees (to be)
• aan die wag = waiting / in the process of waiting

So is aan die wag works a bit like English are waiting.

It adds the idea that the children are currently in that state or activity, not just that they wait in general.

It is understandable, but many speakers would often say the simpler:

Die kinders wag vir hul beurt om die kos te proe.

Afrikaans very often uses the simple present where English would use a present continuous form.

So both ideas are possible, but:

• wag = very common, neutral, natural
• is aan die wag = more explicitly ongoing, and can sound a bit more marked or colloquial depending on the speaker

Because the verb is wag vir = wait for.

So:

• Ek wag vir die bus. = I am waiting for the bus.
• Hulle wag vir hul beurt. = They are waiting for their turn.

The vir belongs with the verb wag here, just like for belongs with wait in English.

Here hul is the possessive determiner meaning their.

So:

• hul beurt = their turn

In careful standard Afrikaans, hul is commonly used before a noun:

• hul huis = their house
• hul kinders = their children

Hulle is usually the pronoun they/them, and it can also appear in less formal usage where some speakers might say hulle beurt, but hul beurt is the standard written form here.

Because the idea is their turn as a single turn belonging to them in the situation.

Even though kinders is plural, the noun after the possessive can still be singular if the thing possessed is understood as one item at a time.

Compare English:

• The children are waiting for their turn.

You would normally say turn, not turns, unless you specifically meant several separate turns.

This is an infinitive construction.

• om introduces the infinitive phrase
• te marks the infinitive
• proe is the verb taste

So om die kos te proe means to taste the food.

After a noun like beurt, Afrikaans often uses om ... te + verb:

• ’n kans om te leer = a chance to learn
• my beurt om te praat = my turn to speak

So hul beurt om die kos te proe means their turn to taste the food.

Because in Afrikaans infinitive clauses, the object often comes before the infinitive verb.

So Afrikaans says:

• om die kos te proe

literally something like:

• to the food to taste

That may feel unusual to an English speaker, but it is normal Afrikaans word order.

You can see the same pattern elsewhere:

• Ek wil die kos proe.
• Dis lekker om die kos te proe.

In both cases, die kos comes before the verb proe.

Structurally, it most naturally goes with beurt.

So the sentence groups like this:

Die kinders is aan die wag
vir hul beurt
om die kos te proe

In other words:

• they are waiting
• for their turn
• to taste the food

So om die kos te proe explains what the turn is for.

Because they are doing different jobs.

• is is the auxiliary verb in the progressive-like expression is aan die wag
• wag is the main action of the first part
• proe is the verb in the infinitive phrase om die kos te proe

So the sentence contains:

1. a main clause about waiting
2. an infinitive phrase about tasting the food

This is very normal in Afrikaans, just as English can have more than one verb in a sentence:

• The children are waiting for their turn to taste the food.