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...
My inner monologue is an asshole that literally never shuts up unless I'm asleep. If I'm not actively thinking about something and conversing with him or keeping him otherwise distracted, he's singing a snippet of the last catchy song he heard, over and over, until a new one takes its place. Sometimes it's the same song for days on end.