Future which invokes the platform specific method for getVoices
Returns a List of Maps containing a voice name and locale
For iOS specifically, it also includes quality, gender, and identifier
Android, iOS, and macOS supported only
Future which invokes the platform specific method for areLanguagesInstalled
Returns a HashMap with true or false for each submitted language.
Android supported only
Future which invokes the platform specific method for setQueueMode
0 means QUEUE_FLUSH - Queue mode where all entries in the playback queue (media to be played and text to be synthesized) are dropped and replaced by the new entry.
Queues are flushed with respect to a given calling app. Entries in the queue from other calls are not discarded.
1 means QUEUE_ADD - Queue mode where the new entry is added at the end of the playback queue.
Android supported only
Future which invokes the platform specific method for setSilence
0 means start the utterance immediately. If the value is greater than zero a silence period in milliseconds is set according to the parameter
Android supported only