It's been talked about many times -- VoiceAttack has nothing to do with the native Windows Speech Recognition Application which has been deprecated by Windows and set for removal, to be replaced by the "Speech Access" application instead.
The underlying Speech API (SAPI) is not changing and is not being removed, and will continue to be used indefinitely by Windows for applications which make use of it (like VoiceAttack).
To be clear: VoiceAttack is presently not related to the existing (deprecated) Speech Recognition App or the newcomer "Speech Access" App, either. The SAPI that all of these applications use is not changing or being removed.