Learn Hardcore Turkish: Bulaşık süngerini değiştiriyorum, çünkü eski sünger kokuyor. - I am replacing the dish sponge because the old one smells.

Because it’s a definite direct object. In Turkish, a specific object takes the accusative. Here, bulaşık sünger-i-ni = dish sponge + compound marker (-i) + accusative (-(n)i with the buffer -n). It means “the dish sponge” (the one we’re talking about), not sponges in general.

Why does bulaşık süngeri already have an -i? Is that possession?

In noun–noun compounds (like “dish sponge”), Turkish marks the head noun with a suffix that looks like 3rd person possessive: bulaşık sünger-i. Here it’s a compound marker, not real possession. With a real possessor you’d say, for example, Ali’nin süngeri (Ali’s sponge).

Could I say Bulaşık süngeri değiştiriyorum without the accusative?

Yes, but it changes the meaning. Without accusative it’s indefinite/generic: “I (habitually) change dish sponges / I’m changing a dish sponge (not a specific one).” With -ni, it’s definite: “I’m changing the dish sponge (the specific one).” In this context, the definite form is the natural choice.

Why is it eski sünger (old sponge) and not eski süngeri as the subject?

Subjects don’t take accusative in Turkish, and definiteness isn’t marked on subjects. Eski sünger is the subject in the reason clause and stays unmarked.

What’s the structure of değiştiriyorum?

değiş-tir-iyor-um

değiş: change
-tir: causative (make something change → “change [something]”)
-iyor: present continuous
-um: 1st person singular So it means “I am changing (it).”

What’s the difference between değiştiriyorum and değişiyorum?

değiştiriyorum: transitive, “I am changing (something).”
değişiyorum: intransitive, “I am changing (myself/it is I who change).” Here you need the transitive form because you’re changing a sponge.

Could I use değiştiririm instead?

değiştiririm (aorist) usually expresses habitual action, general truth, or a promise/offer (“I change/I will change/I can change it”). For an action in progress right now, değiştiriyorum is the natural choice.

How is kokuyor formed, and why -uyor (not -iyor)?

From kokmak (to smell). The progressive suffix harmonizes: since the last vowel in the stem kok- is back and rounded (o), you get -uyor → kok-uyor = “it is smelling.”

Does kokuyor imply a bad smell by default?

Often yes; kokuyor on its own tends to imply an unpleasant smell. To be explicit:

Bad: kötü/pis/berbat kokuyor
Good: güzel/hoş/mis gibi kokuyor

Is the comma before çünkü required?

It’s standard to put a comma before çünkü when the reason clause follows the main clause. Omitting it in casual writing isn’t catastrophic, but the comma is recommended.

Can I start the sentence with çünkü?

Not as a single combined sentence with the result after it. In writing you either say:

Main clause, çünkü reason clause (as given), or
Two sentences: “Bulaşık süngerini değiştiriyorum. Çünkü eski sünger kokuyor.” If you want the reason first in one sentence, use a different structure (see below).

How can I say “because” without çünkü?

Use -DIĞI için:

Eski sünger koktuğu için bulaşık süngerini değiştiriyorum. Here kok-tuğ-u is a nominalized clause (“the fact that it smells”), + için (“because”).

What about using diye for “because”?

That works too:

Eski sünger kokuyor diye bulaşık süngerini değiştiriyorum. This attaches the reason with diye and is common in speech.

What’s the difference between çünkü and bu yüzden/o yüzden?

çünkü introduces the reason: “..., because ...”
bu yüzden/o yüzden gives a result: “..., therefore/so ...” Example: Eski sünger kokuyor, bu yüzden bulaşık süngerini değiştiriyorum.

Can I replace bulaşık süngerini with a pronoun?

Yes: Onu değiştiriyorum, çünkü eski sünger kokuyor.
onu = “it” as a direct object (accusative of o).

Do I need to say ben?

No. The ending -um in değiştiriyorum already marks 1st person singular. Ben is optional for emphasis or contrast.

How would I say it for multiple sponges?

Object plural: Bulaşık süngerlerini değiştiriyorum... (“I’m changing the dish sponges”)
Subject plural: Eski süngerler kokuyor. (“The old sponges smell.”)

Does bulaşık mean “dirty” here?

In compounds like bulaşık süngeri, bulaşık means “dishes” (as in dishwashing). It can also mean “dirty” in other contexts, but here it’s “dish sponge.”