I could be wrong here, but it seems to me that a common aspect amongst all languages is the tendency to raise the pitch of your voice slightly when asking a question. Especially at the end of a question sentence.
If I’m wrong about this raised pitch being common amongst all languages, at the very least do all languages change their tone slightly to indicate that a question is being asked?
I guess there needs to be some way to indicate what is and isn’t a question. Perhaps a higher pitched voice reflects uncertainty. Is this something deep rooted in humans, or just an arbitrary choice when language developed?
That’s just a coincidence. 吗, meaning “what?”, is pronounced má which has the ascending tone. This is not true of all questions in Chinese. For example: 谁在你的右边 meaning “who is on your right?” does not end with 吗, and 边 is pronounced bian which has the flat tone.