M.G. Siegler:

Basically, whether I’m in Safari or Pocket or Medium reading, I use the iOS ‘Speak Selection’ functionality to read things to me. You can do this almost anywhere within iOS (once you enable the feature in ‘Settings’) by selecting a block of text and hitting ‘Speak.’

Or, I find the real key is to enable ‘Speak Screen’ which allows you to quickly trigger the contents of any screen to be read to you simply by swiping two fingers down on an iOS screen.

This needs to be more widely known.