Speech begins in the mind. Whether we say something out loud or silently to our self, we are still saying something. We may not move the air to sound it out but the muscles used to vocalize the words still receive a signal from the brain. This subvocal speech can be perceived through electromyography by measuring the electrical potential created by muscle cells in the throat when they receive a speech signal from the brain. Electrodes on the neck capture the subvocal speech and the silent communication is converted into audible speech.
The simple human act of talking involves a complex set of systems. The science of speech is concerned with anatomy, neuroanatomy, physiology, and acoustics. Phonation is the production of sound during vocalization when muscle contractions in the larynx and the movement of breath are used to vibrate the vocal folds and modulate air flow from the lungs. But even when the acoustic aspects of phonation are removed we are still speaking in our head and the other systems of speech are still active. Activity in the muscle cells involved in the phonation of the words can be convert during silent thought to speech using subvocal recognition.
The verbal mind has a strong attachment to speech. We listen to our thoughts, consciously and subconsciously, that are spoken quietly in the mind. And when we read we say the words silently in our head. Listening to your thoughts can feel like having a conversation with yourself. Silencing the subvocal voice is central to many traditions of religious and spiritual practice. Meditation is a tool for feeling equanimity towards your thoughts until the subvocal voice ceases to speak. But subvocalization is also used in many of the same traditions in the form of prayer where the subvocal voice is used to speak to God.
Subvocal recognition technology is applied in circumstances when vocal communication is compromised or not possible. Pilots, astronauts, and divers can use subvocal speech to communicate with one another in conditions when vocal acoustic speech is not possible. Subvocal recognition was also developed by the military as a way of communicating during combat or hostage situations.
Synthetic telepathy is a form of silent communication that uses subvocalization in brain-computer (or mind-machine) interfaces where external devices are manipulated with the mind. Direct neural interfaces also involve the use of electroencephalography or EEG to measure changes of voltage in the brain. BCIs are designed primarily for aiding, enhancing, and restoring cognitive or sensory-motor functions. What role will silent communication play in future interface designs for mobile computing and other interaction technologies?
Our mind speaks to us and we speak to our mind. But who is speaking? Who is our conscious voice and who is our subconscious voice? Does is our subvocal voice come from the conscious mind while the subconscious mind operates silently? Or does subvocal speech originate in both the conscious and subconscious minds? What does subvocal speech show us about the power dynamics that exist between the conscious and subconscious minds? Who is the alpha? Who is submissive? Do they switch roles? And are they speaking to each other even when we’re not listening? What is the rest of us saying when we’re not speaking?
the E X P E R I M E N T
From the moment I arrived at school until necessary in class I am only speaking with subvocalization. I met Sarah and Mack in the morning to participate in their looping conversation experiment. When I was asked why I wasn’t speaking I told them. But they didn’t hear me. Sarah called it a vow of silence and Mack called me silent TK. I felt calm and peaceful. But I also felt like I was missing the excitement and happiness that comes with banter and conversation. Sarah and Mack are two exceptional cases of people I like to share banter and in both cases they are people that I really enjoying riffing together with wit and humor. Not only was I withholding from this fun activity and missing the positive reinforcement, I was also soon ignored. When I was spoken to it was with a lightness that came with the oddity of my condition but I noticed how quickly I seem forgotten in the group.
I tried to stay in the conversation with subvocal speech but I was talked over and rarely had a chance to speak with out being interrupted. During the exercise Mack and Sarah repeated to one another, “I don’t care what you think Mack.”
“I don’t care what you think Sara”. For sixty minutes straight.