HRESULT UtteranceBegin(QWORD qTimeStampBegin);
Notifies the application that the engine has detected the beginning of an utterance or sound.
· Return value is ignored.
qTimeStampBegin
[in] Time, in bytes, when the sound began.
Detecting the beginning of an utterance doesn't necessarily have any bearing on the recognition of words or the completion of a phrase. Because a call to UtteranceBegin implicitly signals the end of the silence, an application can use this function to detect long periods of silence and react accordingly.