In the evolution of audio technology, we’ve achieved remarkable duality in output: speakers for public listening and earphones for private, personal audio. Yet for input, we remain stuck in a singular paradigm: the microphone. Whether dictating notes, issuing voice commands, or conversing with AI systems, audio input inherently broadcasts our interactions. This lack of privacy has significant implications, from awkward moments in public spaces to limitations in environments where sound isn’t an option.
Unspoken aims to challenge this status quo. By combining ultrasound and laser speckle sensing, we’ve developed a novel silent speech detection system that bridges the gap in audio input privacy. Offered in multiple form factors, Unspoken provides a private, wearable alternative to microphones—enabling users to interact with technology through subvocalized speech without making a sound.
The disparity between public and private modes of communication becomes apparent when we examine our reliance on microphones. Unlike the versatility of earphones, microphones inherently capture sound in ways that are:
By contrast, Unspoken envisions a world where private audio input is as seamless and ubiquitous as personal audio output. Whether dictating a response during a crowded commute, issuing commands in a quiet library, or interacting with AI systems in a secure environment, Unspoken makes private communication truly private.
The core of Unspoken lies in its sensing technologies, which capture silent speech through subtle physiological signals:
Ultrasound sensors detect minute vibrations in the jaw and throat as a user subvocalizes speech. These vibrations are imperceptible to others but carry the acoustic information necessary to reconstruct speech. This technique enables highly accurate detection without requiring audible sound.
Laser speckle sensing captures microscopic surface movements on the skin, such as those caused by tongue and lip motion during subvocalization. These tiny displacements are analyzed using machine learning models to extract phoneme patterns, enabling precise speech reconstruction even in noisy or dynamic environments.
By combining these two modalities, Unspoken achieves robust, low-latency silent speech detection that adapts to diverse usage scenarios.
One of the key design goals for Unspoken was to offer flexibility in how and where the technology is used. We developed multiple form factors to suit different contexts:
These form factors ensure that Unspoken can be adopted across a wide range of scenarios, from private conversations to hands-free command environments.
Building Unspoken required solving several critical challenges at the intersection of HCI, sensing, and machine learning:
Unspoken isn’t just a technology—it’s a rethinking of how we interact with machines. By enabling private, silent speech input, it opens up possibilities that traditional microphones can’t support:
As we move toward a future where voice interfaces become increasingly central to our technology, Unspoken fills a critical gap. It ensures that voice input is as flexible, accessible, and private as the rest of our interaction toolkit.
In designing Unspoken, our goal wasn’t just to create a better input device—it was to address a fundamental limitation in how we think about communication. By offering silent, private speech detection, Unspoken redefines what’s possible in voice interaction, making it more inclusive, adaptive, and human-centered.
As audio input evolves to meet the needs of a connected world, we believe privacy should be at its core. With Unspoken, we’re one step closer to that vision—a future where speaking doesn’t mean being overheard, and interaction feels as personal as thought itself.