Ons ontsyfer vinnig terwyl die horlosie aftel.

Ons means we.

In Afrikaans, ons is used for we / us, depending on the role in the sentence.
Here it is the subject, so it means we:

• Ons ontsyfer ... = We decipher ...

Unlike English, Afrikaans does not change this word to a different subject form like we vs us in the same way in everyday use.

Afrikaans verbs are much simpler than English verbs.

The verb here is ontsyfer = to decipher / decode. In the present tense, Afrikaans usually uses the same verb form for all subjects:

• Ek ontsyfer = I decipher
• Jy ontsyfer = you decipher
• Ons ontsyfer = we decipher
• Hulle ontsyfer = they decipher

So there is no extra ending like English deciphers, and no separate -ing form here. Afrikaans often uses the simple present where English might use either decipher or are deciphering, depending on context.

The word in the sentence is ontsyfer, and it commonly means:

• to decipher
• to decode
• sometimes to work out / figure out something written or coded

So its exact English translation depends on context. In this sentence, it suggests we are deciphering/decoding quickly.

Vinnig means quickly here, so it is functioning as an adverb.

• Ons ontsyfer vinnig = We decipher quickly

A useful thing to know is that Afrikaans often uses the same word for both adjective and adverb:

• ’n vinnige antwoord = a quick answer
• Hy antwoord vinnig = He answers quickly

So vinnig can mean quick in some contexts and quickly in others, depending on how it is used.

Terwyl means while.

It introduces a clause that describes something happening at the same time:

• Ons ontsyfer vinnig terwyl die horlosie aftel.
  = We decipher quickly while the clock counts down.

In some contexts, terwyl can also have a contrastive sense like whereas, but in this sentence it clearly means while in the time sense.

Yes. Die here means the.

So:

• die horlosie = the clock / the watch

Afrikaans uses die as the definite article for all nouns. Unlike languages such as German or Dutch, Afrikaans does not change the word for the based on gender.

So you can think of:

• die man = the man
• die vrou = the woman
• die horlosie = the clock/watch

It can mean either clock or watch, depending on context.

In this sentence, because it is counting down, English would most naturally say the clock:

• die horlosie aftel = the clock counts down

If the context were about something on your wrist, it could mean watch instead.

Excellent question. Aftel is a separable verb meaning to count down.

In a main clause, separable verbs usually split:

• Die horlosie tel af. = The clock counts down.

But after a subordinating word like terwyl, the verb usually goes to the end, and the separated parts come back together:

• ... terwyl die horlosie aftel.

So this sentence shows a very common pattern:

• main clause: tel af
• subordinate clause: aftel

That is why you see aftel as one word here.

Because terwyl introduces a subordinate clause, and subordinate clauses in Afrikaans usually push the verb to the end.

Compare:

• Main clause: Die horlosie tel af.
• Subordinate clause: ... terwyl die horlosie aftel.

So the structure is:

• terwyl
  • subject + other elements + verb at the end

This is one of the most important word-order patterns in Afrikaans.

Afrikaans often uses the simple present where English prefers the present continuous.

So:

• die horlosie tel af
• literally: the clock counts down
• natural English: the clock is counting down

Likewise:

• Ons ontsyfer vinnig
• literally: We decipher quickly
• natural English in context: We’re deciphering quickly

Afrikaans can express ongoing action in other ways, but the plain present tense is very common and natural.

Not in this exact structure.

Because the clause after terwyl is subordinate, aftel is the correct form:

• ... terwyl die horlosie aftel.

If you made it into a separate main clause, then it would split:

• Die horlosie tel af.

So both forms are correct, but each belongs to a different sentence structure.

Vinnig can sometimes move, but Ons ontsyfer vinnig is a normal and natural order.

You may also see:

• Ons ontsyfer die kode vinnig.
• Ons ontsyfer vinnig die kode.
  This is possible in some contexts, but can sound more marked or less neutral.

For a learner, the safest pattern is:

• subject + verb + adverb

So:

• Ons ontsyfer vinnig ...

is a good standard structure to remember.