In "Witcher 3: Songs of the Past," CD Projekt Red utilized artificial intelligence to modify the voice of the original Polish actor portraying Geralt.

CD Projekt Red employed artificial intelligence to modify the voice of Jacek Rozenek, Geralt's original Polish actor, for the "Songs of the Past" expansion of The Witcher 3. Rozenek had a stroke in 2019, which temporarily impaired his speech. During an interview with Game File, he shared that his recovery involved extensive daily voice training.

Although Rozenek was part of The Witcher 3's 2022 next-gen update, the voice recording sessions were challenging for him. CD Projekt Red aimed to include him in the expansion but acknowledged the noticeable evolution of his voice since the game's initial release twelve years ago.

Mikołaj Szwed, the localisation producer at CD Projekt Red, noted the difference between Rozenek's current voice and his earlier recordings might disrupt the player's immersion. The unique nature of this circumstance prompted the company to collaborate with Respeecher, a Ukrainian firm specializing in AI, to bring his voice closer to its original sound with Rozenek's approval.

Rozenek expressed confidence in the game's developers, explaining that the AI's purpose was to closely replicate his voice from 2014. Respeecher's AI was trained with his previous recordings to match his current performances to his younger voice. Respeecher's Dmytro Vasylets detailed the process as complex, particularly in capturing the emotional nuances vital in Rozenek's performance.

Szwed underscored CD Projekt Red's commitment to ethical AI usage, ensuring actors' consent is secured before employing AI voice replication. This scenario highlights a potential positive application of AI through voluntary collaboration. The broader use of AI in voice acting remains contentious, leading to new guidelines issued by the Japan Actors' Union on unauthorized AI-generated voice replication.

These guidelines state that performances generated by AI should be considered original works, necessitating fair compensation. Similarly, UKIE has teamed up with Sheridans to provide a service that helps UK gaming studios navigate AI usage lawfully and ethically.