Apple's iOS 27 beta 5 has arrived, bringing with it a meaningful expansion of Siri voice customization. The latest beta widens the availability of the new Pace and Expressivity sliders, which first appeared in earlier beta releases. What was once limited to just two brand-new American-accented voices is now available across a much broader set of Siri's voice options. This change may seem like a minor tweak at first, but it is part of a larger effort by Apple to make Siri sound more natural, expressive, and user-controllable.
A Closer Look at Pace and Expressivity
The Pace and Expressivity controls are designed to give users direct influence over how Siri speaks. Pace refers to the speed at which Siri delivers words, while Expressivity controls the amount of emotion and emphasis in the voice. These two parameters are not entirely new concepts in text-to-speech systems, but Apple has integrated them into Siri in a way that feels remarkably intuitive. In the latest beta, you can adjust both sliders to one of five distinct levels. This granularity allows users to fine-tune the voice to match their preference, whether they want a quick, efficient response or a more conversational and emotive tone.
To access these controls, you simply navigate to Settings, then Siri, then Voice. Once there, you will see the Pace and Expressivity sliders. Moving the sliders provides near-instant previews, allowing you to hear the effect of each adjustment. Apple has designed the interface to be straightforward, making it easy for anyone to customize Siri without diving into complex configuration menus.
Expanded Voice Support
The key change in beta 5 is the expansion of these sliders to additional voices. In earlier betas, only the two newly introduced American voices supported the new controls. Now, the customization is available for any American accent voice that Siri offers, along with all existing British accent voices. This means there are now eleven supported voices that allow users to adjust pace and expressivity. For those keeping count, that includes eight American voice options and four British voice options on a modern iPhone. The expansion suggests that Apple's new neural-based voice synthesis models are now being applied more broadly across the Siri voice lineup.
Apple has been gradually evolving Siri's voice portfolio for years. Originally, Siri launched with a single American female voice, and later added male and female options in multiple languages and regions. Over time, Apple introduced voice variations designed to sound more natural, using advanced machine learning techniques. The new voice options introduced with iOS 27 are a significant leap forward, as they are generated by a powerful on-device model that can adapt to different speaking styles in real time.
The Hardware Behind the New Voices
The technology driving these advanced voice features is not available on every device. Apple has stated that the new Siri voices take advantage of a powerful new on-device model. As a result, there are specific hardware requirements that users need to meet in order to access the full experience. The feature requires an iPhone 17 Pro or iPhone 17 Air, an iPad Pro (M4) or newer, or a Mac with an M3 chip or newer and at least 12 GB of RAM. These are fairly recent hardware requirements, which may disappoint some users, but they also indicate the computational intensity needed to generate highly natural speech with adjustable emotional nuances.
This on-device approach is a cornerstone of Apple's privacy-focused AI strategy. By processing speech synthesis locally, Apple avoids sending voice data to remote servers, which preserves user privacy and reduces latency. The trade-off is that the software demands a certain level of processing power and memory. Apple's own chips have become increasingly capable, and the company is clearly leveraging that performance to power features that were previously only possible in the cloud.
Older Devices and Siri AI
It is important to distinguish between the new voice synthesis and the more comprehensive Siri AI coming later this year. Siri AI, which is Apple's broader artificial intelligence overhaul, requires an iPhone 15 Pro or newer. However, older devices are not completely left out. They will still receive traditional Siri voice synthesis, but without the newest voice customization options or the same level of naturalness. On supported devices, the full Siri AI experience will launch in beta sometime later this year. This staggered rollout is similar to how Apple has handled major software features in the past, gradually expanding capabilities as it gathers user feedback and optimizes performance.
The difference between Siri AI and the voice customization features is subtle but important. Siri AI refers to the deep integration of language models and generative AI into Siri's decision-making and conversational capabilities. The voice customization features are about the physical sound of Siri's voice, the way syllables are emphasized, and the overall rhythm of speech. Both are significant upgrades, but they are independent of each other to some degree. The expansion of voice customization in iOS 27 beta 5 is an encouraging sign that Apple is still dedicated to refining the fundamentals of Siri's speech, even as it pushes forward with more ambitious AI features.
How to Experience the New Voices
If you are running iOS 27 beta 5 on a compatible device, trying out the new voice customization is simple. Start by opening the Settings app and navigating to the Siri section. From there, select Voice. You will see a list of available Siri voices, split by accent and gender. When you select a voice that supports the new controls, you will see the Pace and Expressivity sliders appear. The sliders are clearly labeled and allow you to choose from five levels for each setting. As you adjust the sliders, Siri will play a sample phrase so you can hear the difference instantly. Once you are satisfied with the sound, your selection is automatically saved and will be used across Siri interactions system-wide.
It is worth noting that the voice customization feature is not confined to one specific language or region. While the current expansion focuses on American and British English voices, it is likely that Apple will extend the same capabilities to other languages and accents in future beta releases. Historically, Apple has introduced new Siri features with a limited set of languages and then expanded them over time. For example, when Siri first gained neural voices, the rollout began with a handful of languages before gradually spreading to all supported regions.
The Evolution of Siri's Voice
Since Siri's introduction in 2011, the assistant's voice has undergone several transformations. The original voice was synthesized using concatenative text-to-speech, which relied on recorded snippets of human speech stitched together. This method produced functional but robotic-sounding results. With iOS 14, Apple switched to neural text-to-speech, which uses machine learning models to generate speech from scratch. That change made Siri's voice much more natural and fluid.
Now, with iOS 27, Apple is taking that a step further by giving users direct control over the emotional and rhythmic aspects of Siri's speech. The Pace and Expressivity sliders are a natural evolution of Siri's voice customization, allowing individuals to shape the assistant's vocal style in ways that were previously impossible. For accessibility, this is also a meaningful improvement. Users who have difficulty understanding fast speech can slow Siri down, while those who prefer a more energetic voice can increase expressivity.
The expansion in beta 5 is a clear signal that Apple is listening to user feedback. In earlier beta releases, many users were excited about the new sliders but disappointed that they were limited to so few voices. Now, with support for all American and British voices, the feature is much more inclusive. It also demonstrates Apple's commitment to iterating quickly during the beta period, as the company continues to shape iOS 27 into a polished release for this fall.
Source: 9to5Mac News