subvocal

Subvocalization, or silent speech, is the internal speech typically made when reading; it provides the sound of the word as it is read. This is a natural process when reading and it helps the mind to access meanings to comprehend and remember what is read, potentially reducing cognitive load. The term merges the internal speech with involuntary minute movement of muscles associated with speaking, which does not require the literal moving of one's lips. Most of these movements are undetectable (without the aid of machines) by the person who is reading. It is highly debatable whether such involuntary action has the same impact on faster reading as loud internal speech has.