Learn Hardcore Turkish: Ben yemek yaparken kardeşim masayı hazırlıyor. - While I am cooking, my sibling sets the table.

yaparken is the standard, neutral form and very common.
yapıyorken is also used, but it tends to sound more colloquial and often emphasizes the ongoing nature of the action (“right in the middle of doing”).

In your sentence:

Ben yemek yaparken kardeşim masayı hazırlıyor.
Sounds completely natural and is what you would usually say.

You could also hear:

Ben yemek yapıyorken kardeşim masayı hazırlıyor.

For a learner, it’s safer to stick with yaparken and similar forms like gelirken, giderken, uyurken, etc. They’re the most common and always correct in this kind of sentence.

Why do we say yemek yapmak instead of using a single verb for “to cook”?

In Turkish, yemek basically means food / meal, and yapmak means to make / to do.

So yemek yapmak literally is “to make food”, which corresponds well to English “to cook”.

Other natural options you’ll hear:

yemek pişirmek – to cook food (literally “to cook food”)
yemek hazırlamak – to prepare food

All of these can mean “to cook (a meal).”
In this sentence, yemek yapmak is simply a very common way to say “to cook (food)”.

Why is Ben written? Can it be left out?

Normally in Turkish you can drop subject pronouns, because the verb ending already shows who the subject is. For example:

Yemek yapıyorum. = I am cooking. (No Ben needed.)

However, in your sentence there are two different subjects:

Ben yemek yaparken – I am the one cooking.
kardeşim masayı hazırlıyor – my sibling is the one setting the table.

If you remove Ben:

Yemek yaparken kardeşim masayı hazırlıyor.

Turkish speakers will very naturally read it as:

While my sibling is cooking, my sibling is setting the table.
(i.e. the same subject for both actions, which is odd.)

So here, Ben is important to show that:

I am doing the cooking,
my sibling is doing the table-setting.

You could also say:

Ben yemek yaparken o masayı hazırlıyor. – While I am cooking, he/she is setting the table.

Why don’t we say benim kardeşim for “my sibling”? How is possession shown?

In Turkish, possession is mainly shown with suffixes, not with a separate word like my.

kardeş – sibling
kardeş
- -im → kardeşim = my sibling

The word benim also means my, but it’s usually optional. You add benim only for emphasis or contrast:

kardeşim – my sibling (normal, neutral)
benim kardeşim – my sibling (as opposed to someone else’s)

In this sentence, simple kardeşim is enough, because nothing is being contrasted.

Does kardeşim mean “brother” or “sister”? Is it gender-specific?

kardeş is gender-neutral. It means sibling in general.

kardeşim can mean:
- my brother,
- my sister,
- or just my sibling, when gender doesn’t matter or is unknown.

In everyday speech, people also use:

abim – my older brother
ablam – my older sister
erkek kardeşim – my (younger) brother
kız kardeşim – my (younger) sister

But in this sentence, kardeşim simply tells you it’s my sibling, without specifying gender.

Why is it masayı and not just masa? What does the -yı ending do?

-yı here is the accusative case ending, marking a definite direct object (the thing directly affected by the verb).

masa – table
masa
- -yı → masayı – the table

In Turkish:

When the direct object is definite/specific, you must use the accusative:
- Masayı hazırlıyor. – He/She is preparing/setting the table.
When it’s indefinite / non-specific, you leave it bare:
- Masa hazırlıyor. – He/She is preparing a table / tables (unspecified).

The -y- is just a buffer consonant used because masa ends in a vowel; it helps connect masa + -ı smoothly:

masa + ı → masayı, not masaı.

In the phrase masayı hazırlamak, it’s clearly about “setting the (specific) table”, so the accusative -yı is required.

Why is the word order kardeşim masayı hazırlıyor and not kardeşim hazırlıyor masayı?

Basic Turkish word order is:

Subject – (objects / adverbs) – Verb

So:

kardeşim – subject
masayı – direct object
hazırlıyor – verb

→ kardeşim masayı hazırlıyor is the default, neutral order.

You can move things around for emphasis, but it changes the focus or can sound odd:

Kardeşim masayı hazırlıyor. – neutral: “My sibling is setting the table.”
Masayı kardeşim hazırlıyor. – emphasizes kardeşim: “It’s my sibling (not someone else) who is setting the table.”

But kardeşim hazırlıyor masayı is not a natural everyday order. Keeping the object just before the verb is a good rule of thumb.

Can we put the clauses in the opposite order, like Kardeşim masayı hazırlıyor ben yemek yaparken?

Yes, you can put the main clause first and the -ken clause after it, but the feel changes slightly.

Your original:

Ben yemek yaparken kardeşim masayı hazırlıyor.
Neutral flow: “While I am cooking, my sibling is setting the table.”

Reversed:

Kardeşim masayı hazırlıyor ben yemek yaparken.
Feels more like:
“My sibling is setting the table, (and) it’s while I am cooking that this happens.”

This order is more marked (less neutral) and often used for emphasis or in spoken language with a specific intonation.

Most of the time, especially in writing or in neutral speech, the -ken clause comes before the main clause:

… yaparken, … hazırlıyor.

How would this sentence change in the past or future tense?

You mostly change the tense of the main verb (hazırlıyor) and keep yaparken as it is.

Past continuous – “While I was cooking, my sibling was setting the table.”
- Ben yemek yaparken kardeşim masayı hazırlıyordu.
- hazırlıyor → hazırlıyor-du (was setting)
Simple past – “While I was cooking, my sibling set the table.”
- Ben yemek yaparken kardeşim masayı hazırladı.
Future – “While I am cooking, my sibling will set the table.”
- Ben yemek yaparken kardeşim masayı hazırlayacak.
Future + future (more general planning):
- Ben yemek yaparken kardeşim masayı hazırlayacak.
  Still works as “While I’m (going to be) cooking, my sibling will set the table.”

So:

yaparken often stays as “while (I) cook / am cooking”,
and the time reference is mainly carried by the main clause verb.

Does -ken always mean two actions at exactly the same time, or can it also mean “when”?

-ken usually expresses overlap in time (“while, as”) but it can also be translated as “when” in many contexts.

Examples:

Yemek yaparken müzik dinliyorum.
→ I listen to music while I cook.
Otobüse binerken kartımı kaybettim.
→ I lost my card when I was getting on the bus.
Çocukken İstanbul’da yaşıyordum.
→ When I was a child, I lived in Istanbul.

So in your sentence:

Ben yemek yaparken kardeşim masayı hazırlıyor.
Means that the two actions overlap:
- while I am in the process of cooking,
- at that same time, my sibling is setting the table.

Why is there no word like “and” (ve) in the Turkish sentence?

English uses “and” to connect actions:

“I am cooking and my sibling is setting the table.”

In Turkish, the suffix -ken already contains the idea of connection + time (“while / as”), so another conjunction is not needed:

Ben yemek yaparken kardeşim masayı hazırlıyor.
Literally: I (while-cooking) my sibling the-table is-preparing.

Using ve here would be ungrammatical or very unnatural:

✗ Ben yemek yaparken ve kardeşim masayı hazırlıyor. (wrong)

So, -ken does the job of both connecting the clauses and showing that they happen at the same time.