The one that surprised me the most was the inability to replay music in your head. Probably because I do that a lot. Here's a series of things you could try.

The one that surprised me the most was the inability to replay music in your head. Probably because I do that a lot. Here's a series of things you could try. - Sing "Twinkle Twinkle Little Star" out loud. - Do it again silently -- don't vocalize -- but keep moving your mouth, lips and tongue. If you're like me, you'll also still feel your throat and vocal chords moving. - Do it again silently, without moving your lips, but still move your tongue and vocal chords. - Do it again silently, but keep your tongue still, just move your vocal chords silently. - Do it again, entirely silently, in your head. I'd be interested to learn which steps are hard for you. When I'm singing a song "in my head" I'm actually doing any one of the latter three actions. Relatedly, when I'm talking to myself in my head -- which I do often, usually while reliving an old conversation or anticipating a new one -- I often do the throat and tongue motions. Occasionally I even do the mouth motions, which is a good way to get people to look at you strangely :)