how does one sync text with audio plus a bit more?

I have created a text script (pdf)specifically for an intermediate foreign language learning program to be sold online. I intend to record the audio and convert it to an MP3 file. (There are two different speakers, the teacher and the student, during the audio.) I also want the script in the target language and its translation to appear onscreen synced with the audio with a user option of hiding either or both of the script texts.  I would like to add images at various points through out the program that represent the audio content.  Audio should have slow play without affecting the pitch as well as loop features that remain sycned with subtitles.  Program should also provide an option for interactive multiple choice  and yes/no questions throughout the video.  Program needs to be accesible to all/most platforms (i.e. desktop and laptop computers and smart phone and tablet devices.)

Any ideas of how to get this done?  Thanks