The Witcher 3 Devs Explain Using AI To Help With Geralt’s Polish Voice In Songs Of The Past: ‘This Is One Of Those Ways Where You Can Use AI Ethically’

Voice actor Jacek Rozenek plays Geralt of Rivia in the Polish version of The Witcher 3, but in 2019 he suffered a stroke that made it hard to speak and changed his voice. CD Projekt Red faced a choice for the upcoming Songs of the Past expansion: swap actors, or turn to AI to help match Rozenek’s new performance with the one he did for the 2015 release. The studio chose the latter. “I can tell you, as a person working with voice actors over all the regions in the world, this is a big concern,” localization producer Mikołaj Szwed told Game File in a new interview about the process. He added, “I do think this is one of those ways where you can use AI ethically, with consent and also to do something good.” Game File reports that CDPR turned to Ukrainian AI voice cloning firm Respeecher for help, the same company it worked with when one of the voice actors for Cyberpunk 2077 died between the release of the original game release and that of the Phantom Liberty expansion. It trains an algorithm on someone’s existing voice work in order to match new performances to the tone and style of the originals. The actors, or their estates, have to consent. “The point is that this voice should be as close as possible to my voice from 12 years ago,” Rozenek told Game File. “I have great trust…for the creators of this game.” He continued, “When it comes to the dynamics of the voice, when it comes to the acting aspects, I feel very good, really very good,” he said. “I can play this role. Of course, it’s very good that this voice will be matched.” The actor recorded over 10,000 lines for the original game, work that Respeecher used in creating its algorithm for his voice. “Getting there took dozens of hours, training models, going through the details with the CDPR team, and dealing with AI artifacts that never fully disappear,” Dmytro Vasylets, a synthetic speech artist for the company, told Game File. “The hardest part was Jacek’s emotional range: the half-tones, shouts, groans, anger, fear and laughter. Capturing all of that at the highest audio quality was the real challenge. I’d like to think we pulled it off.” CDPR said it wasn’t planning to use the algorithm to alter Rozenek’s voice in the future, suggesting that his now lower, gruffier voice would be fine for the appearance of an older, gruffier Geralt in a game like The Witcher 4. The voice actor, meanwhile, confirmed he has not listened to his AI doppelganger and it doesn’t sound like he’s planning to anytime soon.