Toe ek die brief oopgemaak het, het 'n foto uit die koevert op die vloer geval.

Here toe means when, not then.

In Afrikaans, toe often introduces a past-time clause in storytelling or narration:

• Toe ek die brief oopgemaak het = When I opened the letter

So in this sentence, toe is introducing the time at which the next event happened.

Because after toe, Afrikaans uses subordinate-clause word order.

In that kind of clause, the finite verb goes to the end. In the perfect tense, that means:

• subject: ek
• object: die brief
• past participle: oopgemaak
• auxiliary: het

So the order is:

Toe ek die brief oopgemaak het

This is normal Afrikaans grammar for a subordinate clause.

Because there are two clauses, and each clause has its own verb phrase.

1. Toe ek die brief oopgemaak het

   • het belongs to the verb phrase oopgemaak het

2. het 'n foto uit die koevert op die vloer geval

   • het belongs to the verb phrase het ... geval

So each part of the sentence is grammatically complete in its own way.

Because oopmaak is a separable verb made from:

• oop = open
• maak = make

In the past participle, separable verbs usually insert ge between the prefix and the main verb:

• oopmaak → oopgemaak
• toemaak → toegemaak

So oopgemaak is the correct past participle form of oopmaak.

Because Afrikaans main clauses follow the verb-second rule.

The whole first clause, Toe ek die brief oopgemaak het, comes first in the sentence. After that, the main clause must put its finite verb in second position. That is why the next clause begins with het:

Toe ek die brief oopgemaak het, het 'n foto uit die koevert op die vloer geval.

If the time clause were not placed first, you could say:

'n Foto het uit die koevert op die vloer geval.

So the unusual-looking order is caused by the fronted toe clause.

Because Afrikaans usually uses the perfect tense for completed past actions in ordinary language.

So where English often uses a simple past:

• I opened
• a photo fell

Afrikaans very often uses:

• ek het oopgemaak
• 'n foto het geval

This is one of the biggest differences for English speakers. The form with het + past participle is very often the normal way to talk about past events.

Geval is the past participle of val, meaning fall.

The pattern is:

• infinitive: val
• past participle: geval

So:

• het geval = fell / has fallen, depending on context

In this sentence, it refers to a completed past event, so English translates it as fell.

'n is the Afrikaans indefinite article, equivalent to a or an in English.

So:

• 'n foto = a photo

The apostrophe is just part of the normal spelling of this very short word.

A useful extra point: 'n is usually written in lowercase even at the beginning of a sentence. So you would normally write:

• 'n Foto lê op die tafel.

not

• 'N foto lê op die tafel.

Also, in pronunciation, 'n is usually very weak, like a schwa sound.

Afrikaans has just one common definite article: die.

So you get:

• die brief = the letter
• die koevert = the envelope
• die vloer = the floor

Unlike languages such as German, and unlike older Dutch patterns, Afrikaans does not normally change the definite article for gender in this way. That makes article use much simpler.

That order is natural because it gives the movement in a logical sequence:

1. source: uit die koevert = out of the envelope
2. end location: op die vloer = onto / on the floor

So the sentence first tells you where the photo came from, then where it ended up.

Other orders may be possible in special contexts for emphasis, but uit die koevert op die vloer is the most neutral and natural order here.

Yes. When a subordinate clause comes before the main clause, Afrikaans normally uses a comma to separate them.

So this is standard:

Toe ek die brief oopgemaak het, het 'n foto uit die koevert op die vloer geval.

The comma helps show where the toe clause ends and the main clause begins.