Ön yazımda çalışma kültürünü beğendiğimi yazdım.

It means in my cover letter.

Breakdown:

• ön yazı = cover letter
• -m / -ım = my
• -da = in / on / at

So:

ön yazı + m + da → ön yazımda

Turkish often packs ideas like my and in into suffixes instead of using separate words.

Literally, it is something like front writing or introductory writing, but in real usage it means cover letter.

So in job-application contexts, ön yazı is the letter you attach to your CV or résumé.

Here, çalışma kültürü means work culture, working culture, or workplace culture.

The word çalışma comes from çalışmak, which can mean:

• to work
• to study

So çalışma can mean either working/work or studying/study depending on context. Here, because it is followed by kültür, the meaning is clearly work culture, not study culture.

Because it is the specific direct object of beğenmek.

First, the compound is:

• çalışma kültürü = work culture

Then Turkish adds the accusative ending because this is the specific thing being liked:

• çalışma kültürü + -(n)ü → çalışma kültürünü

The n is a buffer consonant. It appears because kültürü already ends with a possessive/compound-type ending.

So:

• çalışma kültürü = work culture
• çalışma kültürünü = the work culture / its work culture, as the object

Because Turkish needs a subordinate clause here, not a second main verb.

In English, you say:

• I wrote that I liked the work culture.

Turkish does not usually put this as two separate finite verbs in the same way. Instead, it turns I liked into a noun-like clause:

• beğendiğimi = that I liked

So:

• beğendim = I liked
• beğendiğimi = that I liked / the fact that I liked

That whole clause becomes the object of yazdım.

It can be broken down like this:

• beğen- = like
• -dik / -diğ- = a clause-forming suffix
• -im = marks the subject as I
• -i = accusative, because the whole clause is the object of yazdım

So:

beğen + dik + im + i → beğendiğimi

In practice, -dik changes shape here and appears as -diğ-.

The result means:

• that I liked
• literally something like my having liked

There is no separate word here. Turkish often expresses that through grammar rather than with an independent word.

In this sentence, beğendiğimi already contains the meaning of:

• that I liked

So the idea of that is built into the subordinate-clause form, especially the -DIK structure plus the personal ending.

Because there are two different layers in the sentence.

Inside the embedded clause

• çalışma kültürünü beğendiğimi
• Here, çalışma kültürünü is the object of beğenmek
• So: I liked the work culture

In the main clause

• beğendiğimi yazdım
• Here, beğendiğimi is the object of yazmak
• So: I wrote that I liked...

So one object belongs to the inner verb, and the other belongs to the main verb.

Because Turkish often leaves subject pronouns out when they are already clear from the verb endings.

You can tell the subject is I from:

• yazdım = I wrote
• beğendiğim- = that I liked

So ben is unnecessary unless you want extra emphasis or contrast.

The word order is somewhat flexible, but the given version is very natural:

Ön yazımda çalışma kültürünü beğendiğimi yazdım.

Turkish usually keeps the main verb at the end, so yazdım naturally comes last.

You could also say:

• Çalışma kültürünü beğendiğimi ön yazımda yazdım.

This is still grammatical, but the emphasis shifts a little. It highlights what you wrote before where you wrote it.

So the order can change, but not completely freely, and the focus changes with it.

No, it is not strange.

• ön yazı is a noun: cover letter
• yazdım is a verb: I wrote

So even though they share the same root, they are doing different jobs in the sentence.

English can do similar things too:

• In my letter, I wrote...

If you wanted to avoid the repetition stylistically, you could use another verb such as belirttim or söyledim, but the original sentence is perfectly normal.