This iPhone app reads OPML outlines outloud. That's all.

http://www.outlinesoutloud.com

The voice is OK. There are very few options, but speech rate can be adjusted. Can skip forward/backward and pause. It's simple purpose is to let you hear your notes. Until I found this app I didn't notice that few (none?) outliners on iOS offer a read-to-me mode.

That's actually quite cool.

I'm a natural speed-reader, and never use audio apps/podcasts etc. But this one really amuses me, for some reason. I suppose it's the outline thing.

I was curious about this and delved into the accessibilty settings in iOS 9 and found that the Speech settings in Accessibility are better than the Outline Outloud app, and don't require messing around with OPML files. I fiddled with Speak Selection and Speak Screen, and turned on Highlight Content. Then, on almost any screen (except, of course, Microsoft apps) a two-finger swipe from the top of the screen starts the reader.