Jack Dorsey posted a demo of a new voice AI called Dessa on Oct. 231. Block, the company he founded, built it to talk the way a real person does, pauses and all2. The post drew 59,024 likes within a day4.
Praise poured in fast. So did a warning. Fraud watchers said the same realism could power the next wave of scam calls2.
Built From Sound Alone
Most voice assistants start as text. A model writes an answer, then a second system reads it aloud. That two-step process is why older assistants can sound flat or stiff1.
Dessa skips that pipeline entirely. It trains straight on recorded human speech, laughs, cries and pauses included2. Block calls the result full-duplex, a model that can listen while it talks, the way two people do on a call1.
A full-duplex model keeps listening while it speaks, so it skips the usual wait for its turn. It can hear a caller interrupt, change tone midsentence, or trail off, and answer in the same beat a person would2.
Block trained the model from scratch on a single Nvidia GB200 NVL72 system, one rack-sized computer2. The result still runs small. A MacBook Pro with an M4 Max chip or better can run Dessa locally, Block says1.
Ragavan Thurairatnam, a researcher on Block's AI team, called it a leap for the field. "This is a GPT3 moment for speech," he said1. GPT-3 marked the point where text generation turned fluent almost overnight, and Thurairatnam's comparison claimed the same leap for speech.
One Post, 59,024 Likes
Dorsey's own words carried the clearest praise. "We believe voice is the most natural way to interact with intelligence, so we created Dessa, the most authentic full-duplex speech model ever built," he wrote on X3. "Talking with it feels like talking with a person…full of emotion, nuance, pauses, and a natural cadence," he added.
Numbers backed up the applause. The post gathered 59,024 likes and 3,510 replies within a day4. Traffic to Dorsey's own Wikipedia page jumped too, to 1,412 views on Oct. 23 from 1,096 views the day before5.
Jack Dorsey's Dessa Post Draws 59,024 Likes for Every 3,510 Replies
Likes and replies on Dorsey's Oct. 23, 2026 post on X introducing Dessa, counted Oct. 24
Each column counts one kind of reaction to the same post; the likes column stands far taller than the replies column.
Source: X (Twitter) syndication API on X [4]. Chart by Kelly Dennis.
The numbers behind this chart
| Item | Value |
|---|---|
| Likes | 59,024 |
| Replies | 3,510 |
What the Applause Drowned Out
The fear aimed past Dessa's own name, straight at the ordinary phone call2. A voice this convincing works on any line, demo included.
Fortune's report carried a case already on the books. A caller told Deborah Del Mastro that a cartel held her daughter, then played a cloned voice crying for help6. Del Mastro wired $5,400 to Mexico over five hours before she reached her daughter directly, safe at work the entire time.
The same report gave the wider numbers. Gallup and the Stop Scams Alliance count $68 billion in U.S. scam losses for 2025, with 12 percent of that total tied to AI or deepfake tools6.
AI or Deepfakes Drove 12 Percent of 2025's $68 Billion in Scam Losses
Share of U.S. scam losses in 2025 that Gallup and the Stop Scams Alliance tie to AI or deepfake tools
Source: Fortune [6]. Chart by Kelly Dennis.
The numbers behind this chart
| Item | Value |
|---|---|
| AI or deepfake scams | 12 |
| Whole | 100 |
A voice clone needs little material to work. McAfee's testers built an 85 percent accurate voice match from a three-second clip of audio6.
Kimberly Hyun, an assistant professor of marketing at the University of Cincinnati's Lindner College of Business, recommends a plain defense6. "You really need to create a safe code with your loved ones," she said. Her advice treats the voice itself as unreliable proof of who is calling.
Why Block Asked Safety Researchers First
Block saw the same risk before anyone posted a warning. The company invited outside safety researchers to test Dessa before anyone else could buy it7.
"We're inviting a small group to explore Dessa, our model trained on speech alone, and help us understand what it can and can't do," Block wrote on X7. The post linked to a sign-up form rather than a public download.
Dessa also carries an old name. Block's research lab includes former staff from a Toronto AI startup also called Dessa, a speech company Square bought in 20202. That earlier Dessa built voice tools years before Block folded the name into its own research effort.
The model stays a research preview for now, open only to the researchers Block picked1. Block kept the release date and the eventual price for a later announcement.
What to do
Pick a private code word with your family this week. Use it whenever a call about money or an emergency feels urgent. A cloned voice can carry real warmth. It rarely carries the word only your family keeps.
Ask any caller who requests money or account access to call you back through a number you already trust. A scam built on a cloned voice depends on speed and panic. Slowing the call down breaks it.
Businesses that use voice AI for support or sales face the same question from the other side. A customer calling in struggles to confirm which voice on the line is synthetic. Saying so upfront, the way Block already discloses Dessa's own research status, costs little and buys trust.
By the numbers
- Likes: 59,024 landed on Dorsey's Oct. 23 post introducing Dessa, counted a day later4.
- Replies: 3,510 gathered under that same post, also counted Oct. 244.
- Pageviews: Dorsey's English Wikipedia page logged 1,412 views on Oct. 23, up from 1,096 the day before5.
- Losses: Gallup and the Stop Scams Alliance count $68 billion in U.S. scam losses for 20256.
- Share: AI or deepfake tools drove 12 percent of those 2025 losses, the same report found6.
- Accuracy: McAfee's testers matched a cloned voice to the original 85 percent of the time, from a three-second clip6.
- Hardware: Block trained Dessa from scratch on a single Nvidia GB200 NVL72 system2.
- Wired: Deborah Del Mastro sent $5,400 to Mexico over five hours before she reached her daughter directly6.
What to watch
Block's safety review is the thing to watch first. A verdict from its outside researchers would show whether Dessa can tell a cloned voice from a real one12. How fast Block moves toward a wider release would show how ready that defense really is.
Sources
- Ivan Mehta, "Block's new voice model sounds eerily human," TechCrunch, Oct. 24, 2026, https://techcrunch.com/2026/10/24/blocks-new-voice-model-sounds-eerily-human/
- Francisco Rodrigues, "Jack Dorsey's new voice AI is impressing users and alarming fraud watchers," CoinDesk, Oct. 24, 2026, https://www.coindesk.com/tech/2026/10/24/block-s-new-voice-ai-sounds-eerily-human-sparking-awe-and-scam-fears
- Jack Dorsey, "We believe voice is the most natural way to interact with intelligence," X, Oct. 23, 2026, https://x.com/jack/status/2113697902916751661
- X (Twitter) syndication API, "Tweet metrics for Jack Dorsey's Oct. 23 post introducing Dessa," X, Oct. 24, 2026, https://cdn.syndication.twimg.com/tweet-result?id=2113697902916751661&token=a
- Wikimedia Foundation, "Pageviews API: Jack Dorsey, en.wikipedia, Oct. 22 to Oct. 24, 2026," Wikimedia Foundation, Oct. 24, 2026, https://wikimedia.org/api/rest_v1/metrics/pageviews/per-article/en.wikipedia/all-access/user/Jack_Dorsey/daily/20261022/20261024
- Muskaan Arshad, "Scammers used AI to clone her daughter's voice and fake a kidnapping. A voice expert says every family needs a safe word," Fortune, Oct. 24, 2026, https://fortune.com/2026/10/24/ai-voice-cloning-scam-fake-kidnapping-safe-word/
- Block, "Calling all AI safety researchers," X, Oct. 23, 2026, https://x.com/blocks/status/2113721026324615173