Alterego is a wearable device that promises to let you silently dictate text by sensing the subvocal movements of your speech muscles.The idea here is not new. The CEO and one of the two co-founders of Alterego, Arnav Kapur, was the lead author of the 2018 MIT research paper AlterEgo, and his new company seeks to spin this off into a real product.The other co-founder, and COO, is Max Newlon, who was the US president of the Chinese BCI startup BrainCo, and has been involved with various neurotech research initiatives.Alterego's co-founders demo the device.For some reason, Alterego seems to be obscuring the true nature of its technology, describing its coming product as a "near-telepathic wearable" that "detects the downstream subtle signals your brain sends to your speech system" to let you "type at the speed of thought", while promising that it won't read the thoughts you don't intend to speak.This has already led the startup to face criticism from experts for misrepresenting itself as a brain-computer interface (BCI), as well as dismissal from laymen who assume the technology, as currently marketed, is exaggerated or an outright scam.But the technology is very real, despite not being a BCI, and Kapur's 2018 paper described it in detail.Like Meta's upcoming wristband, Alterego uses surface electromyography (sEMG) to sense the activation of your muscles. But rather than being attached to your wrist to sense finger muscles, it's attached to the side of your face and senses the speech‐articulator muscles on your face, jaw, and neck.You use these muscles for both audible speech and for what's called subvocalization, the subtle internal speech you might make when reading or mouthing out words. And Alterego's algorithm maps their movement to text.At the time of the 2018 paper, AlterEgo achieved 92% accuracy with around half a second of latency, though these metrics may have improved between then and now.Coverage of the 2018 research.As well as silently dictating text for writing, the Alterego device could be used for discreetly querying an AI assistant, for realtime translated conversations without the awkwardness of hearing the original language, and even to restore speech to people who have lost it or never had it.Details are currently light. Alterego isn't yet revealing a price or release timeline, nor what the cable seen in the demo video is for. But the device could have enormous potential for AR and VR, and could be part of the solution to the long-standing text entry problem.