Amazon's Kindle app does this, as do a few other apps like a the one I used called "speed reader" (the one with a picture of a ninja)... is there anything for a desktop computer that does the same? I found an old thread on this but the link to the software was broken.

I have a browser app that does it called stutter.. I'd just like a desktop program i can load pdfs / epubs etc into and read them this way. If you don't know what RSVP is, check out this sample: https://www.zapreader.com/