Some of the tablets have an option of overriding the App text-to-speech settings, named: "Always Use my Settings" in Text To Speech Settings. If this option is checked then the TTS engine will pick up the User settings for TTS and not the App-specific settings.
My requirement is: whenever my App is using TTS engine, my APP settings should always be used since it has to announce in a particular language at a particular speech rate. But once "Always Use my Settings" is selected and if it has different settings with respect to language and speech rate, then my App's setting is overridden.
Is there any way I can programmatically change this option setting?
This isn't possible. Which makes sense because otherwise it defeats the purpose of "always use my settings".
This comment, as well as my own experiments, support my conclusion.