Ha, interesting! I don't have the control you have on my inner hearing. For a song I love, I can like sing along with my mouth shut, not only the voices, but also the instruments. Strangely, it's hard to have the complete song at the same time (voice + instruments), but I suspect it's more of a skill issue, as I seem to be able to do it faintly.

I'm not envious of the people who have an inescapable inner voice. I think it would hinder my thoughts, the speed of it, and the ability to think abstractly. It's not totally baseless, because I can force myself to have an inner voice, but it's a conscious effort. Sometimes useful if I need to clarify my thoughts. On the same note, not having a inner voice makes it really difficult sometimes to put my emotions and thoughts into words.

But I'm really jealous about anyone that can clearly conjure images, "videos", and sounds in their mind, I feel like I have a big disadvantage if I want to learn to draw, 3D model, or play an instrument.