The vast majority of people have an ongoing conversation with themselves, an inner voice, that plays an important role in their daily lives. But between 5-10 per cent of the population do not have the same experience of an inner voice, and they find it more difficult to perform certain verbal memory...
The same way as listening to someone speak. There's a thread of consciousness that takes in visual data and is translating the written word into a string of syntactical concepts that is then processed analytically.
I was really surprised when I found out that people imagined voices when reading. Wouldn't they be sped up voices? People read faster than speech. It's so confusing...