Learn Turkish: Ben kesin bir yanıt bekliyorum. - I am waiting for an exact reply.

In Turkish, the main focus (vurgu) naturally lands on the word or phrase immediately before the verb. Here, that is kesin bir yanıt (an exact reply). The speaker is heavily emphasizing what they are waiting for, rather than the act of waiting itself.

Since "kesin bir yanıt" is the direct object, why doesn't it have the accusative case ending (yanıtı)?

Because it is an indefinite object (an exact reply, not the exact reply). Indefinite objects in Turkish do not take the accusative case. A crucial rule for sentence structure is that these indefinite, suffix-less objects are "glued" to the pre-verbal focus position—they cannot be moved anywhere else in the sentence.

If the main focus is on the reply, does including "ben" at the start change the emphasis?

Not exactly. While bekliyorum already tells us who is waiting, adding ben at the start of the sentence simply establishes the topic ("As for me, I am..."). It doesn't steal the primary focus, which remains firmly on the phrase right before the verb.

Why is the word order "kesin bir yanıt" instead of "bir kesin yanıt"?

In Turkish, when a noun is modified by both an adjective (kesin, meaning exact/definite) and the indefinite article bir (a/an), the standard order is Adjective + bir + Noun. Thinking of it literally as "exact a reply" can help you remember this pattern!