Kaşarı tostun içine koymadan edemiyorum.

Because it is the direct object of koymak and it is treated as a specific thing, so Turkish uses the accusative ending.

• kaşar = kaşar cheese
• kaşarı = the kaşar cheese / kaşar cheese as a specific direct object

In this sentence, the speaker is not talking about cheese in a completely general way. They mean the particular ingredient they keep putting into the sandwich.

Kaşar is a very common Turkish cheese. It is a mild yellow semi-hard cheese and is especially common in sandwiches and tost.

So kaşarı here means the kaşar cheese as the thing being added.

Not exactly. In Turkish, tost usually means a grilled or pressed sandwich, not just a piece of toasted bread.

So in this sentence, tost is more like a toasted sandwich than English toast.

Tostun içine literally means into the inside of the sandwich.

It breaks down like this:

• tost-un = of the sandwich
• iç-i-ne = into its inside

This is a very common Turkish pattern:

• evin içine = into the house
• çantanın içine = into the bag
• tostun içine = into the sandwich

You could sometimes say tosta koymak, but tostun içine koymak is more explicit and very natural.

Because iç is being used as a possessed noun.

Turkish builds this as:

• tost-un = of the sandwich
• iç-i = its inside
• iç-i-ne = into its inside

So the -i is the possessive ending. This structure is very common in Turkish with words like iç, üst, alt, ön, and arka.

This is a fixed Turkish pattern:

verb + -madan / -meden + edememek

It means:

• cannot help doing
• cannot refrain from doing
• cannot resist doing

So:

• koymadan = without putting
• edemiyorum = I cannot do / I am unable

But together, the meaning is idiomatic:

koymadan edemiyorum = I can’t help putting it

A very literal English unpacking would be:

I am unable to not put it in.

Because this idiom specifically uses -madan / -meden.

The standard pattern is:

verb stem + -madan/-meden + edememek

Examples:

• Gülmeden edemiyorum = I can’t help laughing.
• Sormadan edemem = I can’t help asking.
• Bakmadan edemedi = He/She couldn’t help looking.

So koymadan edemiyorum is the normal idiomatic form.

It comes from etmek and contains negation plus the ability meaning:

• etmek = to do
• ede-memek = to be unable to do
• ede-miyor-um = I cannot / I am not able

But in this sentence, it does not mean physical inability. It means the speaker cannot resist the action.

So here edemiyorum is best understood as something like:

I just can’t help it.

Turkish word order is flexible, and moving something earlier in the sentence often gives it emphasis.

So:

Kaşarı tostun içine koymadan edemiyorum

puts extra focus on kaşarı. It highlights that kaşar cheese is the thing the speaker especially cannot resist adding.

A different order could also be possible, but this version gives more prominence to kaşarı.

The main verb edemiyorum is in the -iyor form. This form often corresponds to the present continuous, but it can also describe something habitual or generally true depending on context.

So this sentence can mean something like:

• I can’t help putting kaşar into the sandwich
• I always end up putting kaşar into the sandwich
• I just can’t resist putting kaşar into the sandwich

The first verb koymadan does not have its own separate tense here. Its time reference comes from the main verb edemiyorum.

It can be either. Turkish often leaves that to context.

It could mean:

• a specific situation right now: the speaker is making a sandwich and cannot resist adding kaşar
• a general habit: whenever the speaker makes a tost, they always end up adding kaşar

So the sentence itself does not force only one interpretation. Context decides.