I decided to give this a whirl myself and I do suspect that something's up.

I am used to most screen readers marking a question in the way that most people do, with a rising intonation at the end of the phrase at the end of the question.

If I enter the sentence, "If there are any questions, please ask them now," followed immediately by, "Any questions?," I don't get any rising intonation at the end of the word "questions" in the question and seem to get additional punch on the "Any".

I am not, however, getting any difference that I can hear on the double question mark version nor the space followed by question mark version in comparison to the conventional punctuation.  I am using NVDA 2016.2.1 on a Windows 10 Home 64-bit machine using the Microsoft SAPI-5 synthesizer and the Microsoft David Desktop English voice with no audio ducking on.
--
Brian

I worry a lot. . . I worry that no matter how cynical you become it's never enough to keep up.