What will Okular, KNotify, and other applications that want to speak to users do instead? The answer is QtSpeech. QtSpeech is a project started by Frederik Gladhorn to bring speech api's to all the platforms that Qt supports. It is still in its infancy, but is quickly improving. A few weeks ago when I built my kf5 stack with kdesrc-build I noticed that kdepim(libs?) was depending on it and it hasn't been released yet, so I got motivated to send some improvements to qt-project. Frederik and Laurent Montel have been pushing fixes and improving it also. It is as easy if not easier to use than the KSpeech dbus api (and doesn't require dbus either) and can be used to speak text on linux/unix, osx, windows, and android platforms so far. If you are an expert on any of these platforms please send patches to implement api on these platforms in their backends, the more eyes on this project the faster we can get it solidified and released.
You may be asking but what about feature X in Jovie that I will miss desperately. Yes there are a few things that QtSpeech will not do that Jovie did. These will either need to be done in individual applications or we can create a small framework to add these features (or possibly add them to QtSpeech itself if they make sense there). The features I'm thinking of are:
1. Filtering - Changing "
2. Voice switching - Changing which voice to use based on the text, or the application it is coming from or anything else. This might make sense in QtSpeech itself, but time will tell if it's a wanted/needed feature.
3. User configuration - Jovie had a decent (not ideal, but it was functional) ui to set some voice preferences, such as which voice you wanted to use, which pitch, volume, speed, gender, etc. This will become the only part of Jovie that will get ported, which is a KDE Control Module for speech-dispatcher settings. This may also change over time, as speech-dispatcher itself possibly grows a ui for it's settings.
All in all, progress is being made. I expect QtSpeech to be ready for release with Qt 5.5, but we'll see what happens.