Yes, DuoBook is a language learning app, so I added RSVP as an add-on feature for re-reading the stories in another language. It’s not the main experience.
My idea was that the learners can do a slow turn with the main reader, and then a quick read afterwards if they want to.
Honestly, I spent at least a week for the pivot alignment but at the end I accepted once in hundred words it’s shifted a bit. I might go back into it at some point though.