Learn Turkish: Kimse töreni izlememiş mi? - Did nobody supposedly watch the ceremony?

The ending -miş is the reported or inferential past tense. By asking izlememiş mi, you are asking about something you didn't see yourself. It translates to "Did nobody supposedly watch it?" or shows surprise based on something you just heard: "Wait, I gather nobody watched it, is that true?". If you just wanted to ask about the plain direct facts, you would use the standard definite past tense: izlemedi mi.

Why is the verb negative (izlememiş) if the English translation uses "nobody watch"?

In Turkish, words like kimse (anybody/nobody) require the verb to also be negative when you want to express a negative idea. Literally, this sentence says "Nobody didn't watch." This double negative is grammatically required in Turkish to say "nobody did it".

Why is it töreni and not just tören?

Tören means ceremony. The -i at the end is the specific direct object (accusative) marker. Because we are talking about watching a specific, known ceremony, the object receiving the action requires this ending.

How exactly is the word izlememiş built?

It starts with the verb root izle (watch). Then we add the negative suffix -me, followed by the reported past tense suffix -miş. Notice that the negative suffix always comes right after the verb root, before any tense suffixes are added.