CD Projekt used AI to smooth Geralt's Polish voice in The Witcher 3 expansion

What CD Projekt changed

CD Projekt Red used a generative AI tool to adjust the Polish voice of Geralt of Rivia in the coming expansion The Witcher 3: Songs of the Past, the studio told journalist Stephen Totilo for his outlet Game File. The tool is Respeecher, a voice synthesis program that uses AI to match one recording to another.

Jacek Rozenek has voiced Geralt in Polish since the first The Witcher game. He recorded all of the new lines for the expansion himself, according to the report. The AI step came after recording, not instead of it.

Why the voice needed matching

In 2019 Rozenek had a serious stroke that caused temporary paralysis on his right side and left him unable to speak for months. He went through a long rehabilitation to return to work.

By the time of the sessions for Songs of the Past, his voice had become rougher and older than in the base game and its first two expansions. The expansion adds new reactions, battle cries and short lines that also play in areas that already exist in The Witcher 3, so a different timbre would have been audible next to the older recordings.

CD Projekt chose Respeecher to keep one consistent voice rather than replace the actor. Rozenek approved the work and said he trusted the studio, according to the report.

The studio's argument

Training Respeecher to get close to the original voice took dozens of hours of extra work, the report says, even though AI tools are often presented as time savers.

Mikołaj Szwed, a producer at CD Projekt Red, described the approach as one of the ethical ways to use AI: with consent, and to do something good, he said.

The studio does not expect to use Respeecher on Rozenek's voice in The Witcher 4. That game features an older Geralt, and the studio expects the actor's changed voice to fit the character.

An earlier case at the same studio

CD Projekt had used Respeecher before, for new lines of the character Viktor Vektor in the Cyberpunk 2077 expansion. The Polish actor who played him, Miłogost Reczek, had died.

In that case the actor's sons agreed to the recreation of their father's voice, which was built from the voice of another actor, according to the report.