Just because you have internal narration doesn’t mean it moves at the same speed as regular speech. Normal speech is limited by the speed at which you can physically move your mouth, not by how fast you can comprehend words/parse meaning. My internal narration moves at roughly 2.5x-3x speed if I were to change my settings. Maybe even a bit higher. But at that speed it sounds garbled to actually listen to a sped-up recording. At the same time I adjust audio to at least 1.6 to 2.2 depending on how slow the narrator is, which is much closer to normal speaking speed than a dramatized narration. The speed at just the regular setting is intolerably slow to me, but I’m a fast talker and always have been.