Definition of subvocalize in US English:

subvocalize

(British subvocalise)

verb

[with object]
  • Utter (words or sounds) with the lips silently or with barely audible sound, especially when talking to oneself, memorizing something, or reading.

    ‘he subvocalized his doubts’
    no object ‘she subvocalized into her intercom’
    • ‘Despite all my training, subvocalizing into a throat mike was very different after the changes reinforcing my mouth and neck.’
    • ‘I could input by subvocalising but I prefer a keyboard, and I could type on a virtual keyboard in the air but I prefer feedback, so keys appear on surfaces near my hands and I type on them.’
    • ‘A clamor of swallowing noises filled his ears, as the crowd subvocalized, carrying on conversations with distant friends.’
    • ‘‘Obviously not a very efficient one,’ subvocalised Jacob.’
    • ‘As she left, she subvocalized, ‘I can talk, Reddie.’’

Pronunciation

subvocalize

/səbˈvōkəˌlīz/