it is not. The voice acting will be implemented in the final game!
Viewing post in Magical Warrior Diamond Heart [Common Route] comments
I've heard the voice acting samples on the Characters page and I think the actors did a decent job with what they were given, and I've watched the VA video previews on your Patreon page and it was alright, though I think it would be nice if the characters actually spoke the dialogue. But all in all, it makes me really anticipated for what the final build brings. Good work.