Galton gave people some very detailed surveys, and found that some people did have mental imagery and others didn't. The ones who did had simply assumed everyone did, and the ones who didn't had simply assumed everyone didn't, to the point of coming up with absurd justifications for why they were lying or misunderstanding the question. There was a wide spectrum of imaging ability, from about five percent of people with perfect eidetic imagery1 to three percent of people completely unable to form mental images2.Dr. Berman dubbed this the Typical mind fallacy : the human tendency to believe that one's own mental structure can be generalized to apply to everyone else's. link
A lot of people have internal chatter. This is a spectrum so some people have this rarely or vaguely, some people hear it in a clear audible way and some even have debates with different voices so if they think about argument with their mom they hear their mom speaking in their head. About 3rd of people don’t have internal monologue at all. I am interested in this topic and this comes as a observation from talking to a lot of people.