Sonic 3.5 is currently in preview on the
sonic-3-latest alias. As with any -latest alias, sonic-3-latest can be updated without notice and is not recommended for production. Pin to a dated sonic-3 snapshot for production traffic.Speed and Volume Controls
Speed and volume controls (including SSML-based controls) are temporarily disabled onsonic-3-latest while Sonic 3.5 is in preview. If you rely on speed or volume augmentation, pin to a dated sonic-3 snapshot for now.
For the controls available today on dated sonic-3 snapshots, see Volume, Speed, and Emotion in Sonic 3 and SSML Tags.