Convert Audio(Wav file) to Text using SAPI?

Question

Hi I am using SAPI My task is to convert an Audio file(Wav) into text not from Microphone. e.g If I have "Hello there" store in wav file to it will transcribe it into text and show "Hello there" string on screen. Any help in this regard will be highly appreciated. I am felt in tough deadlines. Any language code in preferred but priority is c#.