SAPI5

#include <sapi.h>
...
 
bool SpeakText(UnicodeString Text) {
    ISpVoice* pVoice = NULL;
 
    if (FAILED(::CoInitialize(NULL))) return false;
 
    // Disable floating point division by zero exception caused by Speak
    Word Saved8087CW = Default8087CW;
    Set8087CW(0x133f);
 
    HRESULT hr = CoCreateInstance(CLSID_SpVoice, NULL, CLSCTX_ALL,
        IID_ISpVoice, (void **)&pVoice);
    if (SUCCEEDED(hr)) {
        //pVoice->SpeakCompleteEvent()
        //pVoice->SetSyncSpeakTimeout(1000);
        hr = pVoice->Speak(WideString(Text).c_bstr(), SPF_DEFAULT, NULL);
        pVoice->Release();
        pVoice = NULL;
    }
 
    Set8087CW(Saved8087CW);
 
    ::CoUninitialize();
    return true;
}
 
....
SpeakText("key released.");
....