I became aware of this when I first moved away from home and up to where I've been for the last 10 years, living alone, working at getting into an academic program. That first winter I read a lot. A lot. And I found that when I was reading a specific author, it would take me a discrete amount of time to get into his style of writing. In that introductory period which could be fifty pages or a hundred pages or in some cases 800 pages, I would often hear the interior monologue as I was reading. Once I hit my stride though that voice shut off and my speed reading kicked in.