Learn Turkish: Bu soruyu diğer yarışmacı değil, ben yanıtladım. - I answered this question, not the other contestant.

In Turkish, you usually drop the subject pronoun because the verb ending tells you who did the action. However, when you want to emphasize who did it, especially to contrast it with someone else like the other contestant here, you must include the pronoun.

How does the word order show emphasis in this sentence?

In Turkish, the most important piece of new information (the focus) goes right before the verb. By placing ben immediately before yanıtladım, the sentence strongly emphasizes that I was the one who answered it.

How does değil work in the phrase diğer yarışmacı değil?

Değil usually means "not" and is used to negate nouns or adjectives. Here, it creates a direct contrast: diğer yarışmacı değil, ben means "not the other contestant, (but) me." The true subject (ben) is then put into the focus position.

Why is bu soruyu at the very beginning of the sentence?

Since the main point of the sentence is who answered it, the question itself (bu soruyu) is just background information. In Turkish, known background information usually goes at the beginning of the sentence, leaving the pre-verbal spot open for the emphasized information.