I do not believe this has not been studied before. In psychology you talk about the inner monologue, in linguistic you have experiments measuring if silent reading activates muscles in the speech apparatus (as far as I remember, it does), speed reading is all about silencing the inner monologue.<p>A quick search brought this up on Google Scholar:<p><pre><code>    Auditory imagery, D Reisberg - 2014 - 
    books.google.com
    
    &quot;Psychologists have debated the role of inner 
    speech in silent reading, and clinicians ....&quot;</code></pre>