Why does Objective-C use YES/NO macro convention instead of true/false?

Question

Most languages use the true/false keywords for boolean values. I found that even Smalltalk is using true/false. I know Objective-C is just borrow

Answer 1

Objective-C is a very verbose language, all methods are very descriptive, and using YES/NO for boolean values instead of true/false makes it more human readable.

You would probably find the following conversation strange, if it happened in real life: A: "Did you see the movie?" B: "True"

If B had answered "yes" (or "no"), it would sound perfectly normal, and code looks more like plain english by using YES/NO instead of true/false.