Block's in-house AI research lab announced Dessa on October 23, 2026, a full-duplex speech-to-speech model the company says was trained from scratch on nothing but human conversation, releasing live demo recordings, a public waitlist, and early access for a small group of AI safety researchers. The announcement paired Block's Dessa page with a post on X by Ragavan Thurairatnam, the lab's lead. Thurairatnam described Dessa as the first AI model that can hold a realistic conversation after…