Ons sit stil in die klaskamer wanneer die onderwyser praat.

A helpful literal breakdown is:

• Ons = we
• sit = sit
• stil = still / quietly
• in die klaskamer = in the classroom
• wanneer = when / whenever
• die onderwyser = the teacher
• praat = speaks / talks

So even if the full meaning is already known, the structure is quite transparent once you split it up.

Yes, it does literally mean sit still, but in context it can also mean sit quietly or stay seated and quiet.

In a classroom sentence like this, sit stil is very natural because it suggests the kind of behavior teachers want: not moving around, not making noise, and paying attention.

So depending on context, sit stil can feel like:

• sit still
• sit quietly
• be quiet while seated

Because Afrikaans verbs usually do not change according to the subject in the present tense.

For example:

• ek praat = I speak
• jy praat = you speak
• hy praat = he speaks
• ons praat = we speak

The verb stays praat in all of those.

The same is true for sit:

• ek sit
• ons sit
• die onderwyser sit

This is much simpler than English, where you have I speak but he speaks.

In Afrikaans, die is the normal definite article for the.

It does not change for:

• masculine vs. feminine
• singular vs. plural

So:

• die klaskamer = the classroom
• die onderwyser = the teacher
• die klaskamers = the classrooms
• die onderwysers = the teachers

That makes Afrikaans much simpler than languages that have different forms of the.

Because Afrikaans usually writes compound nouns as one word.

So:

• klas
  • kamer → klaskamer

This is very common in Afrikaans. English sometimes writes similar combinations as two words, with a hyphen, or as one word, but Afrikaans is much more consistent about joining them.

So a learner should get used to checking whether a noun combination is really a single compound word.

Wanneer means when, and sometimes whenever, depending on context.

In this sentence, it can mean:

• when the teacher speaks
• whenever the teacher speaks

Because the sentence sounds like a general classroom rule or habit, English could understand it as whenever the teacher speaks.

Also, in everyday speech, some speakers may use as where English uses when, but wanneer is a clear and standard choice here.

Yes, it is a subordinate clause introduced by wanneer.

A useful rule in Afrikaans is that in subordinate clauses, the finite verb usually goes to the end.

Here the clause is:

• wanneer die onderwyser praat

Since there is only one verb, praat, it naturally appears at the end of that clause.

You can also see the word-order pattern if you move the wanneer-clause to the front:

• Wanneer die onderwyser praat, sit ons stil in die klaskamer.

Now the main clause changes to sit ons after the fronted clause. That is normal Afrikaans main-clause word order.

Yes, but the meaning changes a little.

• Ons is stil = We are quiet
• Ons sit stil = We sit still / sit quietly

So is stil focuses more on being quiet in general, while sit stil paints a more specific picture of classroom behavior.

You might also hear:

• Ons bly stil = We remain quiet

That emphasizes continuing to be quiet.

Because praat here is a normal finite verb, not an infinitive.

In this sentence:

• die onderwyser praat = the teacher speaks

That is a complete present-tense clause.

You use om te with an infinitive in other kinds of structures, for example:

• Hy hou daarvan om te praat. = He likes to talk.
• Dit is belangrik om stil te sit. = It is important to sit still.

So in your sentence, om te would be wrong because praat is not functioning as to speak; it is functioning as speaks.

Because stil is not being used before a noun here. It comes after the verb sit, so it stays in its basic form.

Compare:

• die stil kinders = the quiet children
  Here stil is before a noun, so adjective rules may apply.

• Die kinders is stil. = The children are quiet.
• Ons sit stil. = We sit still / quietly.
  Here it stays just stil.

So one useful learner rule is:

• before a noun: adjective forms may change
• after a verb: the word often stays in its simple form

Yes. You can say:

• Wanneer die onderwyser praat, sit ons stil in die klaskamer.

This means the same thing as:

• Ons sit stil in die klaskamer wanneer die onderwyser praat.

The difference is mostly one of emphasis and sentence flow.

When the wanneer-clause comes first, Afrikaans then places the verb before the subject in the main clause:

• sit ons

That is a very common pattern in Afrikaans after a fronted phrase or clause.