SAPI

ふつーにSDKをインストールし，

#define _ATL_APARTMENT_THREADED


#include <sapi.h>
#include <atlbase.h>
//You may derive a class from CComModule and use it if you want to override something, 
//but do not change the name of _Module
extern CComModule _Module;
#include <atlcom.h>

int main(int argc, char* argv[]) {
    if (FAILED(::CoInitialize(NULL)))
        return FALSE;
    
	ISpVoice * pVoice = NULL;
	HRESULT hr = CoCreateInstance(CLSID_SpVoice, NULL, CLSCTX_ALL, IID_ISpVoice, (void **)&pVoice);
    if( SUCCEEDED( hr ) )
    {
		hr = pVoice->Speak(L"Hello world", 0, NULL);
        pVoice->Release();
        pVoice = NULL;
    }

    ::CoUninitialize();
    return TRUE;
}

でしゃべってくれる．