Block unveils Dessa, a speech-only conversation model trained without text
Archived — this story has rotated out of today’s deck. It is kept here in full.
The gist
Jack Dorsey's Block announced Dessa, a full-duplex speech model trained only on human conversation.
It runs on a MacBook Pro, but Block has published no benchmarks, only demos.
Background
Block is Jack Dorsey's fintech company behind Square and Cash App, and Dessa comes from a small AI research lab inside it, led by Ragavan Thurairatnam and reporting directly to Dorsey. Block says the lab has built generative speech models for over eight years, and argues that conventional voice AI converts speech to text and throws away emotion and timing. Dessa is Block's attempt to train a conversational model from scratch on nothing but human speech, the way people learn to speak before they read or write.
How it unfolded
- Oct 23, 2026Block announced Dessa, a full-duplex speech-to-speech model trained from scratch on human conversation with no text and no pretrained models, as a research preview.
- Oct 23, 2026Dessa lead Ragavan Thurairatnam posted on X calling the release "a GPT3 moment for speech" and said it can run on consumer GPUs.
- Oct 24, 2026Block's announcement page described Dessa as the most authentic full-duplex speech model built so far; reports noted it sits behind a waitlist with no parameter count, API, price, weights or published evaluation.
- Oct 24, 2026Block said Dessa was trained on only one NVIDIA GB200 NVL72 and runs locally on a MacBook Pro M4 Max or better, and that a small group of AI safety researchers will get early access to look for unanticipated risks.
Who’s saying what
- Official
- Block says Dessa is the most authentic full-duplex speech model ever built, that talking with it feels like talking with a person, and that it is, as far as Block knows, the world's first AI you can hold a realistic live conversation with that was trained only from human speech.
- Caution
- OrcaRouter notes Block published more than a dozen conversation recordings and not one benchmark number, making the demos the entire public evidence base.
- Analysts
- The Verge described the conversations as "a little awkward and uncanny," flagging one in which Dessa calls its conversation partner "Ronaldo."
Still unverified
Block's performance claims are vendor claims; OrcaRouter states nothing on Block's page has been independently verified. The October 23, 2026 announcement date comes from secondary sources, as Block's own page does not clearly state it. Dessa's real-world accuracy and multilingual capabilities are still under evaluation, and specific technical details remain undisclosed.