Dit is die kaartjie waarvoor ek gister betaal het.

Waarvoor is a prepositional relative word. It is made from:

• waar = a form used for what/which after a preposition
• voor = for

So waarvoor literally works like for which or what ... for.

In this sentence, die kaartjie waarvoor ek gister betaal het means the ticket for which I paid yesterday, or more naturally in English, the ticket that I paid for yesterday.

In Afrikaans, when a relative clause involves a preposition, the language often combines waar- with the preposition:

• waarvoor = for which
• waarin = in which
• waarmee = with which
• waarop = on which

English often leaves the preposition at the end: the ticket that I paid for.
Afrikaans usually does not do that in the same way here. It prefers the combined form waarvoor.

So:

• die kaartjie waarvoor ek betaal het = correct
• die kaartjie wat ek betaal het voor = not natural/incorrect in standard Afrikaans

Because waarvoor ek gister betaal het is a relative clause, and relative clauses in Afrikaans use subordinate-clause word order.

In that word order, the verbs go to the end of the clause.
Since this is the perfect tense, you get:

• betaal
  • het

So:

• main clause: Ek het gister betaal.
• relative clause: waarvoor ek gister betaal het

Notice how in the subordinate clause, het moves to the end.

In a normal main clause, Afrikaans usually puts the finite verb in the second position:

• Ek het gister betaal.

But in a subordinate clause, Afrikaans pushes the verbal elements to the end:

• ... waarvoor ek gister betaal het

So the order changes because of the clause type, not because betaal itself changes.

A useful comparison:

• Ek het daarvoor betaal.
• Dit is die kaartjie waarvoor ek betaal het.

Die here is the definite article, meaning the.

So:

• die kaartjie = the ticket

In Afrikaans, die is used for the with singular and plural nouns:

• die boek = the book
• die boeke = the books
• die kaartjie = the ticket

So Dit is die kaartjie ... means This/It is the ticket ...

Kaartjie is a diminutive form. Afrikaans very often uses diminutives, and -jie / -tjie / -kie endings are common.

From kaart you get kaartjie.

Depending on context, kaartjie can mean things like:

• ticket
• card
• little card

In many everyday situations, kaartjie is simply the normal word for ticket, even if English would not use a diminutive.

So you should not always think of it as little ticket. Often it is just the standard Afrikaans word in context.

Because waarvoor is introducing the relative clause.

The structure is:

• die kaartjie = the noun being described
• waarvoor ek gister betaal het = the clause describing it

Inside that relative clause, ek is still the subject:

• ek ... betaal het = I paid

So waarvoor comes first because it links the clause to kaartjie, and then the subject ek follows.

You can think of it roughly as:

• the ticket [for which] [I] paid yesterday

In subordinate clauses, time words like gister often come before the final verb cluster.

So:

• waarvoor ek gister betaal het

is the normal, natural order.

Afrikaans word order is fairly structured, and adverbs such as gister usually appear before the verbs at the end of a subordinate clause.

That is why you do not get something like:

• waarvoor ek betaal het gister

That sounds unnatural.

Yes. In everyday Afrikaans, Dit is is very often contracted to Dis.

So these are equivalent:

• Dit is die kaartjie waarvoor ek gister betaal het.
• Dis die kaartjie waarvoor ek gister betaal het.

Dis is very common in speech and informal writing.
Dit is can sound a bit more careful or formal.

Yes, normally waarvoor is used for things/concepts, not people.

If a person is involved after a preposition, Afrikaans usually uses a different structure, often with vir wie or another prepositional phrase depending on the context.

For example:

• die persoon vir wie ek gewag het = the person for whom I waited

But with a thing:

• die stoel waarop ek sit = the chair on which I am sitting
• die kaartjie waarvoor ek betaal het = the ticket I paid for

So waar- + preposition is the common pattern for non-human references.

A simple version would be:

• Ek het gister vir die kaartjie betaal.
• or Ek het gister daarvoor betaal, depending on context

Then the relative-clause version turns the ticket into the thing being identified:

• Dit is die kaartjie waarvoor ek gister betaal het.

So the sentence is basically saying:

1. I paid for the ticket yesterday.
2. This is the ticket.
3. Combined: This is the ticket that I paid for yesterday.

That is a very useful way to understand how Afrikaans relative clauses are built.