> I use my inner monologue to sing or hum it in my head, I don't hear it

Wdym? I think that the inner monologue is "hearing it", with a varying degree of vividness between people, of course.

Some people hear orchestral swells when, say, reading a book that mentions them. I don't have that. I have an inner monologue that can sing. I forget the term but as I understand it there are people who don't have an inner monologue. I think many of those would still be able to have "sound" imagery

Some people hear it more like a recording.