The Microsoft Speech API (SAPI) provides a high-level interface between an application and speech engines. SAPI implements all the low-level details needed to control and manage the real-time operations of various speech engines.
The Microsoft Speech API (SAPI) provides a high-level interface between an application and speech engines. SAPI implements all the low-level details needed to control and manage the real-time operations of various speech engines.
The two basic types of SAPI engines are text-to-speech (TTS) systems and speech recognizers. TTS systems synthesize text strings and files into spoken audio using synthetic voices. Speech recognizers convert human spoken audio into readable text strings and files.
API for Text-to-Speech
Applications can control text-to-speech (TTS) using the ISpVoice Component Object Model (COM) interface. Once an application has created an ISpVoice object (see Text-to-Speech Tutorial), the application only needs to call ISpVoice::Speak to generate speech output from some text data.
In addition, the IspVoice interface also provides several methods for changing voice and synthesis properties such as speaking rate ISpVoice::SetRate, output volume ISpVoice::SetVolume and changing the current speaking voice ISpVoice::SetVoice.
API for Speech Recognition
Just as ISpVoice is the main interface for speech synthesis, ISpRecoContext is the main interface for speech recognition. Like the ISpVoice, it is an ISpEventSource, which means that it is the speech application's vehicle for receiving notifications for the requested speech recognition events.
Source:http://msdn.microsoft.com/en-us/library/ee125077(v=vs.85).aspx
