IPA: /sʌbˌvoʊkəlaɪˈzeɪʃən/
KK: /sʌbˌvoʊkəlaɪˈzeɪʃən/
The process of silently pronouncing words in your mind without speaking them out loud.
Many people use subvocalization to help them understand what they are reading.
Subvocalization → It is formed from "sub-" (meaning under or below) and "vocalis" (from Latin, meaning vocal or relating to the voice) and the suffix "-ation" (indicating a process or action). The word describes the process of silently pronouncing words in one's mind, as if under the voice.
Think of the process of speaking 'under' ('sub-') your breath or voice ('vocalis') — that's what subvocalization means.