An era where you can enter text silently just by moving your mouth has arrived. US startup Subvocal has unveiled muscle-recognizing typing glasses capable of input speeds exceeding 200 words per minute.
On October 30 local time, Subvocal announced the launch of pre-orders alongside news that it secured $1.3 million in funding from Y Combinator and Afore Capital. The early bird price is set at $499 (approx. 670,000 won), with the product page also displaying a regular price of $699 (approx. 940,000 won).
Subvocal is a system that reads the movement of speech muscles using radar radio waves rather than cameras. Because radio waves propagate through the air, the method can detect movements beneath the skin without physical contact. Subvocal clarified that it only recognizes words formed by intentionally moving the mouth and does not read thoughts. In video clips, the device demonstrated rapid typing through subtle mouthing motions.
The project originated at Stanford University's hackathon, TreeHacks. In a post on X, Subvocal shared that they initially attached electromyography (EMG) sensors to the face. Using data from silently pronouncing the 26 letters of the alphabet, they trained a model within 24 hours, achieving a character classification accuracy of around 80%.
Since then, they tested four methods: EMG, video, inertial measurement units (IMUs), and radio waves. EMG requires skin contact and its accuracy fluctuates significantly with each use. Webcam video brought the word error rate down to 17%, but because it only tracks the lips, it struggles to distinguish sounds with similar lip shapes, such as 'P' and 'B'. IMUs only capture overall facial movement, showing clear limitations as the vocabulary grows. In contrast, Subvocal claims its current prototype glasses can read continuous speech after about a minute of calibration even for first-time users, achieving a word accuracy of 85–92%.
The company cited a 2022 paper on radar-based silent speech recognition published in the journal Scientific Reports as the foundation for its radio-wave approach.
Products aimed at silent speech input have appeared before. On January 29, Apple acquired Q.ai—an Israeli startup that reads silent speech through subtle movements of facial skin—for $2 billion. In September last year, AlterEgo unveiled a face-wearable originating from research at the Massachusetts Institute of Technology (MIT) Media Lab and demonstrated a video of typing without speaking.
The industry appears to be focusing increasing attention on silent speech recognition, which requires neither manual typing nor vocal sound.
First shipments of Subvocal's glass-type device are expected in the first quarter of 2027. Subvocal added that because the product remains under active development, the schedule may change.
