Die kinders speel binne die huis wanneer dit reën.

Yes. In this sentence, die means the both times:

• die kinders = the children
• die huis = the house

A useful thing to know is that Afrikaans uses die as the definite article for both singular and plural nouns. Unlike English, you do not change it.

Kinders is the plural form of kind, which means child.

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

Afrikaans often forms plurals with endings like -e or -s, but you have to learn the pattern for each noun. Kind → kinders is a very common one.

Usually, no. Afrikaans verbs do not change much according to the subject in the present tense.

So you get:

• ek speel = I play
• jy speel = you play
• die kind speel = the child plays
• die kinders speel = the children play

This is one of the simpler parts of Afrikaans grammar for English speakers.

Binne die huis means inside the house. It emphasizes being indoors, not outside.

In die huis can also mean in the house, and in many contexts it is very similar. But binne gives a clearer sense of inside.

So:

• in die huis = in the house
• binne die huis = inside the house

Here dit works like English it in weather expressions.

• dit reën = it is raining / it rains

It does not refer to a specific thing. It is just the normal subject used with weather verbs, just like in English.

Wanneer means when. It introduces a time clause: when it rains.

In Afrikaans, clauses introduced by words like wanneer are subordinate clauses, and the verb typically goes to the end of that clause. In wanneer dit reën, the clause is very short, so this is not especially noticeable, but reën is still in the expected end position.

For example:

• wanneer dit hard reën = when it rains heavily
• wanneer die kinders binne speel = when the children play inside

In both cases, the finite verb comes at the end of the subordinate clause.

The two dots are called a diaeresis. In reën, they show that the vowels are pronounced separately, rather than blending into one sound.

So you should think of it more like re-en than as a single vowel combination. The spelling helps the reader see the correct pronunciation.

Yes, very often you can. In everyday Afrikaans, as dit reën is very common for a repeated or general situation like when it rains.

So both of these can work:

• Die kinders speel binne die huis wanneer dit reën.
• Die kinders speel binne die huis as dit reën.

Very roughly, wanneer is a more direct when, while as is often used in the sense of when/if in repeated situations.

Yes. You can say:

Wanneer dit reën, speel die kinders binne die huis.

This is very natural. When the subordinate clause comes first, the verb in the main clause comes before the subject:

• speel die kinders
• not die kinders speel

That happens because Afrikaans keeps the finite verb in the second position of the main clause.

It can do either, depending on context, but by itself it most naturally sounds like a general habit or usual situation:

The children play inside the house when it rains.

Afrikaans often uses the simple present tense for both general truths and present-time situations. If you wanted to make the right now meaning more explicit, context usually does that, though Afrikaans can also use other ways to stress an ongoing action.

Literally, huis means house. In many contexts, though, it can feel quite natural in English to translate it as home, depending on the situation.

So this sentence could be understood as:

• The children play inside the house when it rains
• or more naturally in some contexts, The children play indoors at home when it rains

The exact best translation depends on the wider context, even if the Afrikaans word itself is huis.