Apple’s Live Speech feature empowers iPhone, iPad, and Mac users by enabling them to express themselves audibly. This innovative capability allows individuals to type their desired message, which is then vocalized during phone calls, FaceTime conversations, and even face-to-face interactions. Moreover, users have the convenience of saving frequently used phrases for effortless participation in dynamic discussions with loved ones, friends, and coworkers. Live Speech is thoughtfully crafted to provide invaluable support to millions of individuals worldwide who are unable to speak or have experienced a gradual loss of speech.
For users at risk of losing their ability to speak — such as those with a recent diagnosis of ALS (amyotrophic lateral sclerosis) or other conditions that can progressively impact speaking ability — Personal Voice is a simple and secure way to create a voice that sounds like them.
Source: https://www.apple.com/newsroom/2023/05/apple-previews-live-speech-personal-voice-and-more-new-accessibility-features