Allowing a person to go through and edit how some text is read aloud, for example equations. Instead of being read literally, letting a person select or highlight the equation and enter in what it means in natural language.

Example: A{p(t), q(t)} is currently read as "A p t q t" when, in the context of the book, it should be "Some function, A, of the momenta and spatial phase space coordinates".

I don't see a way something very context-dependent could be programmed in, so having a way for the reader to manually change how the equation is interpreted and read might work better.