Speech recognition in Native C

[AMIN]

Hi

I have to make a dll in C/C++ that contains functions to recognize
voice commands, this dll is to be used later in C# with [DllImport]
property.

I researched on System.Speech.Recognition that comes with .net
Framework 3.0, but i don't see any where samples in C++, can anybody
point me any tutorial on how to use System.Speech library in C++ 2.0
version of .net framework.

I am also researching on SAPI 5.1, can anyone tell me which one is
better, system.speech API or SAPI 5.1.
Can anybody suggest me some good tutorials on SAPI 5.1 in visual C++
2005.

Thanks