I think the Spanish question mark indicates that the sentence is going to be a question without suggesting an answer. Languages that lack helping verbs cannot invert the word order to indicate a question as we can in English: She is reading that book is a statement while the question asks Is she reading that book? We don't need the question mark: we know from the inversion of the helping verb and subject that the sentence is a question long before we reach the punctuation.

In Latin, the enclitic particle -ne does not promote an answer: Legisne illum librum? is Are you reading that book? But the two interrogative particles I mentioned, num expecting "no" and nonne expecting "yes," don't reflect the actual answer that the hearer will give, just the answer that the questioner expects. So he won't bite, will he? expects No--but you could still be bitten.

If I asked, he won't bite, will he? and was told, Yes, I would not extend my hand!

Fun questions!