I have also wondered if the two are related. I have aphantasia, and also the majority of inner monologue I experience is when sounding out words during reading.

I have also wondered if the two are related. I have aphantasia, and also the majority of inner monologue I experience is when sounding out words during reading. It's pretty much quiet all the time in my head (which I guess is not everyone's experience?) and much of the thinking seemingly happens at the conceptual level.