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?
Your second question has a general answer. Most languages use tones, which means tones change in the course of a sentence. If the tone changes for all sentences, then it also changes for questions. I know that’s not what you were trying to ask, but that’s the answer to the question you did ask.
If you need a way to indicate that something is a question, you could do what English does… You could use question words at the beginning of the sentence. You could change word order. You could add extra words… Which is to say, you’re not dependent on intonation, though you could use it if you want to.