iOS 27 beta 5 has further expanded the new Siri voice customization options. In earlier betas, the new Pace and Expressivity sliders were only available for the two newly-introduced Siri voices that have an American accent.
Source: [9to5Mac](https://9to5mac.com/2026/08/10/the-new-ios-27-beta-further-expands-siri-voice-customization-options/)