Same issue with figuring out who's who. Some people really can't imagine words being spoken. Most can imagine words being spoken. Some can trigger auditory hallucinations. Many of the people in the middle will label themselves as being on one extreme because they think other middle-people are describing the opposite extreme. Like wow you guys can make yourselves just HEAR things that aren't there? And they're like yeah, I can "hear" it in my mind (they don't actually have the sensation of hearing anything at all).