Well @Bateman,There is a Speed reading application which is called Outread which helps a person to read without any loss in comprehension and appreciation and I think that it only uses a simple text effect to make it work and I think that it can be combined with Beeline Reader which also uses colors to help people to read faster and easier and you find out more about them in the following websites or links -
And I think that that feature of the Outread app which highlights text is called Guided Reading and I think that this will be beneficial to @wayweary’s app.