Imagine checking the weather, skimming the day’s headlines, or finding out the scores from last night’s game without ever switching on the TV, pulling out your smartphone or activating your voice recognition device. Imagine doing these things just by thinking about them. It’s all possible with AlterEgo, silent speech device that turns thought into speech.
Developed by MIT Media Lab researcher Arnav Kapur, AlterEgo is a wearable Artificial Intelligence (AI) enabled device that allows users to receive information using an interface that takes place entirely inside their head.
Kapur presented AlterEgo on the Ted 2019 stage in Vancouver, B.C., Canada. The device works by transcribing a user’s internally articulated speech through AI, then feeds back sensory and audio data using bone audio conduction technology.
“Normally when we speak, the brain sends neuro signals through the nerves to your internal speech systems to activate them and your vocal cords to produce speech,” Kapur said in his Ted talk. “Now, imagine talking to yourself without vocalizing, without moving your mouth, without moving your jaw, but by simply articulating those words internally.”
This action subtly engages the user’s internal speech systems such as the tongue and larynx. This prompts the brain to send extremely weak signals to those systems, that the device picks up.
“AlterEgo has sensors, embedded in a thin plastic, flexible, and transparent device that sits on your neck, just like a sticker,” Kapur explains. “These sensors pick up on these internal signals sourced deep within the mouth cavity, right from the surface of the skin.”
Kapur continues, “An AI program running in the background then tries to figure out what the user’s trying to say. It then feeds back an answer to the user by means of bone conduction — audio conducted through the skull into the user’s inner ear — that the user hears.”
These answers are found online, as with any smart device, but without typical requirements, like typing or speaking out loud.
In short, Kapur likens the process to talking to yourself.
AlterEgo isn’t commercialized yet, but the potential could be far-reaching. A motivating factor in Kapur’s developing the technology was to help individuals who struggle with natural speech. This could impact people dealing with Lou Gehrig’s disease, stroke or oral cancer, by potentially helping them regain the ability to communicate in real-time.
Is it mind reading or something else?
One important point Kapur makes about AlterEgo: it doesn’t read people’s thoughts.
“The control in all situations resides with the user” he said.
His team’s first design principle was to bake ethics right into the design from the start. Rather than pulling information directly from the brain, they focused on requiring deliberate engagement from the user to communicate with the device.

Kapur’s work recently earned him a $15,000 Lemelson-MIT Student Prize. This will help further development of AlterEgo and move Kapur toward his goal of elevating the human experience.
“I believe computing, AI and the internet would disappear into us as extensions of our cognition, instead of being external entities or adversaries, amplifying human ingenuity, giving us unimaginable abilities and unlocking our true potential,” Kapur said. “And perhaps even freeing us to becoming better at being human.”