For the no decodable audio tracks... please verify you have the latest version. Go to the App Store, search for Walkout Song DJ and verify it displays version 2.16.6 and the button says 'open' and not 'update'. If you do have the latest version and you are still getting the error with some songs, I would suggest removing those songs from your iTunes library, add them back, then repick the songs for the players in the Walkout Song app.
Now on the text to speech, it sounds like somehow the speech queue has some screen reading going on. I would check the accessibility settings to see if any screen reading is enabled.