Ek sit die brief in 'n koevert en skryf die adres op die koevert.

In this sentence, sit is being used in a very common Afrikaans way meaning put or place.

So:

• Ek sit die brief in 'n koevert = I put the letter in an envelope

This can feel surprising to English speakers because English sit usually means to be seated. In Afrikaans, though, sit can often be used for placing something somewhere, especially in everyday speech.

A more formal or specific verb could be plaas, but sit is very natural here.

Because both actions have the same subject: I.

Afrikaans, like English, often leaves out the second subject when it is clearly the same:

• Ek sit die brief in 'n koevert en skryf die adres op die koevert.

This works just like English:

• I put the letter in an envelope and write the address on the envelope.

You do not need to repeat Ek before skryf, although you could in some contexts for emphasis:

• Ek sit die brief in 'n koevert en ek skryf die adres op die koevert.

That is grammatical, but less natural unless you want emphasis.

Afrikaans uses:

• die = the
• 'n = a / an

So:

• die brief = the letter
• die adres = the address
• 'n koevert = an envelope

The sentence is talking about a specific letter and a specific address, so die is used. But it introduces the envelope as an envelope, so it uses 'n.

Later, the envelope is now specific, so Afrikaans says:

• op die koevert = on the envelope

This is the same idea as in English:

• I put the letter in an envelope and write the address on the envelope.

'n is the Afrikaans indefinite article, meaning a or an.

A few important things about it:

• It is always written as 'n
• It is usually not stressed in speech
• It is pronounced more like a weak uh sound, not like the letter n

Also, when a sentence starts with 'n, the article itself usually stays lowercase:

• 'n Koevert lê op die tafel.

In standard writing, the first real noun is capitalized if needed, not the 'n.

Afrikaans is much simpler here than many European languages.

Die is the definite article for basically all nouns:

• die brief
• die adres
• die koevert

It does not change for masculine, feminine, or neuter nouns the way articles do in languages like German or Dutch.

That is good news for learners: you usually just learn die as the.

Because the prepositions match the physical idea:

• in 'n koevert = the letter goes inside the envelope
• op die koevert = the address is written on the outside surface of the envelope

So the sentence is very literal and logical:

• put the letter in the envelope
• write the address on the envelope

This is similar to English, so it is a helpful sentence for learning how Afrikaans prepositions often work in straightforward ways.

Afrikaans often repeats the noun where English might use a pronoun. Repeating die koevert sounds clear and natural.

So:

• ... en skryf die adres op die koevert

is perfectly normal.

You could also say:

• ... en skryf die adres daarop

where daarop means on it / on there.

Both are possible, but repeating the noun is often easier and clearer for learners.

Afrikaans verbs are much simpler than English verbs in this respect. In the present tense, the verb usually stays the same regardless of the subject.

For example:

• Ek skryf = I write
• Jy skryf = you write
• Hy skryf = he writes
• Ons skryf = we write

Unlike English, Afrikaans does not usually add an -s for he/she/it in the present tense.

That is why you get:

• Ek sit
• Ek skryf

with the basic verb form.

The basic word order here is very similar to English:

• Ek = subject
• sit = verb
• die brief = object
• in 'n koevert = prepositional phrase

Then the second clause continues:

• en skryf die adres op die koevert

So the structure is basically:

• Subject + verb + object + place
• then
• and + verb + object + place

Afrikaans main clauses normally keep the finite verb early in the clause, often in the second position. In a simple sentence like this, that feels very close to English word order.

In this sentence, brief clearly means letter as in mail or written correspondence.

If context is missing, brief generally suggests a written letter/message rather than a letter of the alphabet.

So here:

• die brief
• 'n koevert
• die adres

all work together to show that this is about mailing or preparing a letter.

Yes. Koevert is the normal word for envelope in standard Afrikaans.

So:

• 'n koevert = an envelope
• die koevert = the envelope

It is a useful everyday word, especially in sentences about letters, mail, and addresses.

Yes, you could.

• Ek sit die brief in 'n koevert sounds natural and everyday.
• Ek plaas die brief in 'n koevert sounds a bit more formal or deliberate, like place in English.

In ordinary speech, sit is very common for putting something somewhere.

Yes. Skryf is the normal Afrikaans verb for write.

So:

• Ek skryf die adres = I write the address

It works much like English write. In this sentence, it means physically writing the address onto the envelope.

A more natural English translation might be:

• I put the letter in an envelope and write the address on the envelope.
• or more naturally:
• I put the letter in an envelope and write the address on it.

The Afrikaans sentence is completely normal even though it repeats die koevert. Afrikaans often keeps things explicit where English might prefer a pronoun.