Learn Hardcore Turkish: Lavabo sifonunun sızdırdığını görünce vanayı kapattım. - When I saw that the sink trap was leaking, I closed the valve.

In this sentence, lavabo sifonu means the sink’s trap (the U- or P-shaped pipe under the sink). Note that sifon can also mean the toilet flush mechanism, but lavabo sifonu specifically refers to the sink trap.

Why is it lavabo sifonunun and not something like lavabonun sifonu?

Lavabo sifonu is a noun–noun compound (“sink trap”), formed as modifier + head with a 3rd‑person possessive on the head: lavabo
- sifon
  - u → lavabo sifonu.
To make that whole compound genitive (because it’s the subject of a nominalized clause), you add the genitive case to the end: lavabo sifonunun.
You could also say lavabonun sifonunun (“the sink’s trap’s…”) and it’s grammatical, but heavier. Lavabo sifonunun treats the trap as a single established item.

Can you break down sızdırdığını morphologically?

Yes:

sız: to seep/leak (intransitive)
-dır: causative, yielding sızdır- “to make leak / allow leakage” (commonly used for things like pipes, roofs, traps)
-DIK: nominalizer → sızdırdık
Consonant/vowel adjustments: sızdırdığı
-ı: 3rd person possessive (agreeing with the genitive subject) → sızdırdığı
-(y)ı accusative; after a possessive you need a buffer n → sızdırdığını
Meaning: “the fact that (it) leaks / is leaking.”

Why do we have both a genitive on lavabo sifonunun and a possessive on sızdırdığını?

This is the standard genitive–possessive agreement in -DIK nominalized clauses:

The subject of the embedded clause takes genitive: lavabo sifonunun (“of the sink trap”).
The nominalized verb takes a possessive suffix agreeing with that subject: sızdırdığı (“its leaking”).
Together they form “the trap’s leaking,” which here is then marked accusative (object of gör-).

Why is sızdırdığını in the accusative?

Because it’s the object of görmek (“to see”). In structures like “X‑i görünce …”, the thing you saw (even if it’s a whole clause) takes accusative. Hence: sızdırdığını.

Is görünce related to görünmek (“to seem/to appear”)?

No. Here it’s gör- (“to see”) + -IncA (when/as soon as) → görünce “upon seeing / when I saw.” The ü is from vowel harmony; it’s not the stem görün-.

Could I say gördüğümde instead of görünce? Any difference?

Yes:

görünce = “when/once I saw; upon seeing” (more immediate, colloquial).
gördüğümde = “when I saw” (slightly more neutral/literary).
gördükten sonra = “after seeing” (emphasizes sequence).
All are acceptable; pick based on nuance.

Why not just sızdığını instead of sızdırdığını?

sızmak focuses on the liquid itself seeping/leaking.
sızdırmak focuses on the object letting something leak (roof, pipe, trap), often with an implied object like su (water).
For a device or fixture, sızdırmak (or colloquially kaçırmak) is very common: Sifon sızdırıyor/kaçırıyor “The trap is leaking.” Sızdığını is not wrong, but sızdırdığını matches the “letting water leak” idea.

What’s the little n doing before the accusative in sızdırdığını?

It’s the mandatory buffer n used when a possessed noun (here the nominalized verb with 3sg possessive) takes a case ending: sızdırdığı (its leaking) + n + ı (ACC) → sızdırdığını.

Why is vanayı accusative?

It’s a definite, specific object: “the valve.” In Turkish, definite direct objects take accusative: vanayı kapattım “I closed the valve.” If it were indefinite, you’d use the bare noun: Vana kapattım “I (closed) a valve,” or add bir: Bir vana kapattım.

Is kapatmak the right verb for “turn off/close” here?

Yes. kapatmak covers “to close/shut” and “to turn off” (water, gas, devices). You can also hear kapamak (variant), e.g., kapadım, but kapatmak/kapattım is more common.

Why the double t in kapattım?

Stem: kapat-
Past: -DI → harmonizes/assimilates to -tı after a voiceless consonant → kapattı
1sg: -m → kapattım
So the double t is just stem-final t plus the past tense allomorph -tı.

Any vowel harmony points I should notice?

gör + -IncA → görünce: front and rounding harmony give ü.
sifon + u + nun → sifonunun: possessive -u
- genitive -nun with back vowels.
sızdırdığını: all suffix vowels harmonize with the stem.
vana + -(y)ı → vanayı: front/back harmony and buffer y after a vowel.

Can I change the word order?

Yes, within limits for clarity/emphasis:

Default: Lavabo sifonunun sızdırdığını görünce vanayı kapattım.
Focus on the action taken: Vanayı, lavabo sifonunun sızdırdığını görünce kapattım. Keep X’i görünce together: put the thing seen (sızdırdığını) before görünce; Görünce sızdırdığını is unnatural.

Could I shorten it if context is clear?

Yes. If “sink trap” is already known, you can drop it: Sızdırdığını görünce vanayı kapattım. Or replace with a pronoun subject for the nominalized clause: Onun sızdırdığını görünce… (here onun = “its/his/her,” so make sure it’s not ambiguous in context).

Is there a more “immediate” way to say “as soon as I saw…”?

Use -Ir … -mez: Sızdırdığını görür görmez vanayı kapattım. = “As soon as I saw it was leaking, I closed the valve.”