Learn Hardcore Turkish: Flüt sesi gecenin sessizliğini böldü. - The sound of the flute broke the stillness of the night.

Turkish is an S–O–V language. In this sentence:
• Subject (S): Flüt sesi (“the flute sound”)
• Object (O): gecenin sessizliğini (“the night’s silence,” definite direct object)
• Verb (V): böldü (“broke”)

Why does Flüt have no suffix, while sesi ends in -i?

Here Flüt sesi is an attributive compound meaning “flute sound.” In such compounds the first noun (Flüt) remains bare, and the second noun (ses) takes the 3rd person singular possessive suffix -i to show “sound of a flute.”
You could also use the full genitive-possessive construction—Flütün sesi—if you want to be extra explicit (“the flute’s sound”).

What exactly is the suffix -i on sesi, and why is it -i?

This -i is the 3rd person singular possessive suffix, marking “its sound.”
By Turkish vowel harmony, after the stem vowel e (in ses) you choose -i (not -ı, -u, or -ü), giving sesi.

How is gecenin sessizliğini constructed? Why does sessizlik carry two suffixes?

Break it down:

gecenin = gece (night) + buffer n
- genitive -in → “of the night.”
sessizliğini = sessizlik (silence) + possessive -i (3rd person) + accusative -ni → “its silence” as a definite object.
– The possessive -i shows “silence of the night.”
– The accusative -ni marks it as a specific direct object of böldü.

Why does the object phrase take the accusative, i.e. -ni on sessizliğini?

In Turkish, a definite or specific direct object must be marked with the accusative suffix -ı/-i/-u/-ü (here realized as -ni because it follows the possessive -i). Since we mean “the night’s silence” (not just “a silence”), it gets the suffix.

How does vowel harmony determine which vowel appears in these suffixes?

Turkish has two harmony dimensions:
• “Four‐way” harmony for -I suffixes (i, ı, u, ü): pick the vowel closest in front/back and rounded/unrounded to the stem’s last vowel.
• “Four‐way” harmony for -In suffixes (in, ın, un, ün) follows the same rule.
Examples in our sentence:
• ses (e → front unrounded) + -i = sesi
• gece (e → front unrounded) + buffer n + -in = gecenin
• sessizlik (i → front unrounded) + -i (poss.) + -n (acc.) = sessizliğini

Why is there a buffer n in gecenin, whereas other suffixes sometimes use y (e.g. arabayı)?

Different suffixes use different buffer consonants when attaching to a vowel-final stem. The genitive suffix -nI always uses n as a buffer:
• gece + n + in = gecenin
By contrast, the accusative -yI uses y:
• araba + y + ı = arabayı

Could we replace bölmek with bozmak here, as in “break the silence”?

Yes. sessizliği bozmak (“to disturb/disrupt the silence”) is very common. bölmek literally means “to split” or “to cut through,” giving a more poetic image: “the flute sound cut through the night’s silence.”

Can I make the possessor fully explicit by marking Flüt with a genitive?

Absolutely. The fully marked version is Flütün sesi gecenin sessizliğini böldü. Here you have:
• Flüt-ün (genitive: of the flute)
• ses-i (possessive: its sound)
• gece-nin (genitive: of the night)
• sessizlik-i-ni (possessive + accusative on “silence”)