Teyzem karpuzu keserken ben şeftalileri yıkayacağım.

Teyzem means my maternal aunt.

It breaks down like this:

• teyze = maternal aunt
• -m = my

So teyzem literally means my aunt. More specifically, it is your mother’s sister or sometimes your mother’s female cousin/aunt figure, depending on family usage.

A useful contrast:

• teyze = maternal aunt
• hala = paternal aunt

In Turkish, possession is often shown with a suffix on the noun instead of a separate word.

So instead of saying something like my aunt with a separate word for my, Turkish says:

• teyze = aunt
• teyzem = my aunt

This is very common in Turkish:

• annem = my mother
• babam = my father
• evim = my house

So the -m in teyzem is doing the job of my.

Those endings show that they are direct objects, and in this sentence they are specific/definite ones.

Breakdown:

• karpuz = watermelon

• karpuzu = the watermelon / a specific watermelon

• şeftali = peach
• şeftaliler = peaches
• şeftalileri = the peaches / specific peaches

In Turkish, specific direct objects usually take the accusative ending.

So here:

• karpuz-u
• şeftali-ler-i

The -ler part is the plural ending, and the final -i marks the object as specific.

Because the sentence is talking about:

• one watermelon → karpuzu
• more than one peach → şeftalileri

So the grammar matches the meaning:

• karpuz stays singular
• şeftali becomes plural with -ler

This is completely normal. Turkish marks number directly on the noun when needed.

Keserken comes from the verb kesmek, meaning to cut.

In this sentence, -ken gives the idea of:

• while
• when
• during the time that

So keserken means while cutting or when she is cutting.

In the sentence, teyzem karpuzu keserken means:

while my aunt is cutting the watermelon

This -ken form is very common for showing two actions happening at the same time.

Because Turkish often leaves pronouns out when they are already clear from context.

Here, the subject of keserken is already stated: teyzem.

So Turkish does not need to say o for she. The phrase already clearly means:

my aunt, while cutting the watermelon...

This is very natural in Turkish.

Yıkayacağım means I will wash.

It is built like this:

• yıka- = wash
• -y- = buffer consonant
• -acak = future tense suffix
• -ım = first person singular, I

So the structure is:

yıka + y + acak + ım

This becomes yıkayacağım.

A couple of useful notes:

• The -acak future suffix appears here because of vowel harmony.
• The k changes to ğ before the personal ending, which is why you get -acağım, not -acakım.

So the whole word already includes the meaning of I will wash.

No, ben is not strictly necessary.

Turkish verbs already show the person, and yıkayacağım already means I will wash.

So the sentence could simply be:

Teyzem karpuzu keserken şeftalileri yıkayacağım.

That would still be grammatical.

However, ben is added for emphasis or contrast. It helps highlight the change of subject:

• teyzem = my aunt
• ben = I

So the sentence feels like:

While my aunt cuts the watermelon, I will wash the peaches.

The ben makes that contrast clearer.

Because Turkish often puts the time/background information before the main action.

So this order:

Teyzem karpuzu keserken ben şeftalileri yıkayacağım.

naturally sets the scene first:

• While my aunt is cutting the watermelon...
• I will wash the peaches.

This is very natural Turkish word order.

Turkish word order is fairly flexible, so other arrangements are possible, but this version sounds smooth and clear.

It means the actions overlap in time.

So the idea is:

• during the time my aunt is cutting the watermelon,
• I will wash the peaches.

It does not have to mean they begin at the exact same second or finish at the exact same second. The important idea is that one action happens while the other is going on.

Turkish does not have articles that work exactly like English the and a/an.

Instead, definiteness is often shown by:

• context
• word order
• accusative marking on direct objects

That is why karpuzu and şeftalileri can naturally correspond to:

• the watermelon
• the peaches

So even without a separate word meaning the, Turkish still expresses that idea.

A few letters here are especially important for English speakers:

• ş = sh as in ship
  • şeftali
• ı = a vowel with no exact English equivalent; it is a dull, unrounded vowel
  • heard in yıkayacağım
• ğ = usually not a strong g sound; it often lengthens the vowel before it or creates a light glide
  • in yıkayacağım
• c = j as in jam
  • in -acağım

So yıkayacağım is not pronounced with a hard g. The ğ is very soft.