subvocal

They’re actually hearing their own “subvocal speech”—the unconscious muttering that we all do, and that people with schizophrenia are unable to disregard.

This result meant that when the schizophrenics were hearing voices in their heads, their vocal muscles were contracting—they were engaging in subvocal speech.

But what if subvocal speech was just very quiet, and nobody but the patient could hear it?

He thought to himself: If subvocal speech is a slight activation of the vocal muscles, leading to the production of extremely quiet sound, what if we were to make it louder?

This phenomenon is called subvocal speech, and it happens all the time.