After an application has created an audio-destination object, its next task is to find a suitable engine and text-to-speech mode and to create an instance of the engine object to represent the mode. An engine typically provides an assortment of text-to-speech modes that it can use to play text in different voices or audio sampling rates.
An application finds a suitable engine and text-to-speech mode by creating a text-to-speech enumerator and using it to find a mode and engine that meet the application's criteria. An application can also enumerate all available modes and select an engine and mode from the list.