Learn Turkish: Yazılı olarak feshetmediğiniz takdirde yükümlülük devam eder. - In the event that you do not terminate it in writing, the obligation continues.

Both express a condition, but the structure in this lesson (Verb + -dIğI + possessive + takdirde) is highly formal. While feshetmezseniz is just "if you don't terminate," using takdirde translates to "in the event that you do not terminate." You will see this heavily in contracts, official warnings, and legal documents.

Why is feshetmediğiniz written as one word instead of fesih etmediğiniz?

The noun fesih (cancellation) comes from Arabic. When it combines with the helper verb etmek, the vowel -i- in the second syllable drops out. In Turkish grammar, when this type of vowel elision occurs, the noun and the helper verb must be written together as a single word: feshetmek.

What role does olarak play in yazılı olarak?

Olarak literally means "as" or "being" (from olmak). Here, it turns the adjective yazılı (written) into the adverbial phrase yazılı olarak (in a written manner / in writing). This is the standard way to express doing something "in writing" in formal Turkish.

How is the noun yükümlülük (obligation) built from its root?