Called when the TTS engine informs the engine service user about whole supported language and voice type list. This callback function is implemented by the engine service user, therefore, the engine developer does NOT have to implement this callback function.
public delegate bool SupportedVoice(string language, VoiceType type, IntPtr userData);
The language is specified as an ISO 3166 alpha-2 two-letter country code followed by an ISO 639-1 for the two-letter language code. For example, "ko_KR" for Korean, "en_US" for American English.
The voice type.
The user data passed from ForEachSupportedVoices().
true to continue with the next iteration of the loop, false to break out of the loop.
This callback function is called by ForEachSupportedVoices() to inform the whole supported voice list. userData must be transferred from ForEachSupportedVoices().