Hi,

Seem this API just supports Visual Basic and you can't apply it in your c# code. But altermatively, you can try  System.Speech Namespaces which contain types that support speech recognition.

http://msdn.microsoft.com/en-us/library/gg145021.aspx

Bwt, the both references may be helpful to you:

http://msdn.microsoft.com/en-us/library/ms720176(v=VS.85).aspx

http://social.msdn.microsoft.com/Forums/en/csharpgeneral/thread/75d83177-a058-483e-be84-3dc96dec7cef