Learn Hardcore Turkish: Mülakata katılmadan önce başvuru formunu doldurdum. - I filled out the application form before attending the interview.

-madan is a compound suffix made of the negative marker -ma and a verbal noun ending -dan, which together create a temporal clause meaning “before doing X.” Here katıl (to attend) + -ma (negation) + -dan (the gerundial ending) → katılmadan = “before attending.”

Why is it -madan and not -meden in katılmadan?

Turkish vowel harmony dictates that the negative suffix -ma/-me and the gerundial -dan/-den adjust to the vowels in the verb stem. Since katıl has a back vowel ı, the correct harmony pair is -ma + -dan = -madan.

What extra nuance does önce add in katılmadan önce?

önce literally means “before.” When you say katılmadan önce, you’re being explicit: “before attending.” Technically katılmadan already conveys “before attending,” but adding önce makes the sequence of actions crystal clear and is more idiomatic.

Could you drop önce and just say Mülakata katılmadan başvuru formunu doldurdum?

Yes. Mülakata katılmadan başvuru formunu doldurdum is perfectly grammatical and means the same: “I filled out the application form before attending the interview.” Native speakers often include önce for clarity, but it’s not strictly required.

Why does mülakat take the suffix -a in mülakata?

mülakat (interview) is the place or event you go to, so it takes the dative case suffix -a (= “to”). Mülakata katıldım = “I attended the interview” (literally, “I participated to the interview”).

Why is başvuru formunu in the accusative case (with -nu)?

In Turkish, a direct object that is definite or specific takes the accusative suffix -u/-ü/-ı/-i according to vowel harmony. Here başvuru formu (“the application form”) is specific, so it becomes başvuru formu-nu.

Why is the verb doldurdum at the end of the sentence?

Turkish is an SOV (Subject-Object-Verb) language. Even though “I” (ben) is omitted, the order remains:
Subject (implied “I”) + Object (başvuru formunu) + Verb (doldurdum).

Can you use the past perfect (-mişti) instead of the simple past here?

You could say Mülakata katılmadan önce başvuru formunu doldurmuştum (“I had filled out the form before attending the interview”), but it’s usually redundant. The -madan önce clause already signals that one action preceded the other, so the simple past doldurdum is more common.

How would you say “After filling out the application form, I attended the interview”?

You’d switch to the post-action suffix -dıktan sonra:
Başvuru formunu doldurduktan sonra mülakata katıldım.

Is it possible to explicitly include the subject “I” in Turkish?

Yes. You can say Ben mülakata katılmadan önce başvuru formunu doldurdum, but since Turkish verbs are conjugated for person, the pronoun ben is usually dropped unless you want to emphasize the subject.