Breakdown of Zaten bu iftirayı ispatlayamaz ki!
bu
this
zaten
anyway, in any case
ki
but ... (trailing particle of exasperation)
iftira
slander / false accusation
Questions & Answers about Zaten bu iftirayı ispatlayamaz ki!
What exactly does the trailing ki add to this sentence?
It adds a strong sense of exasperation or emphasizes that the statement is obvious. In English, we might express this tone by saying 'I mean, he can't prove it anyway!' or by heavily stressing the word 'anyway'. It shows the speaker thinks the situation is ridiculous because the proof is impossible.
Since zaten already means 'anyway', isn't ki redundant here?
Grammatically yes, but emotionally no! Zaten sets up the logical fact ('in any case'), while ki at the end acts as an emotional amplifier. Together, they create a very natural, conversational tone of dismissal or frustration.
How is the verb ispatlayamaz built to mean 'he can't prove'?
The 'can't' (inability) is hidden in the letter a (along with the buffer y) right before the negative suffix. The root is ispatla- (to prove). To say 'he doesn't prove' (regular negative aorist), you'd say ispatlamaz. To say 'he cannot prove', you add the ability vowel -a before the negative, giving us ispatla-y-a-maz.
Why is there a -yı at the end of iftirayı?