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.