Speech, but not in an audible tone, an accent, or any particular distinctive feature, they are simply thoughts. Nor to they feel like they are spoken, they are nothing but a word that my mind dwells on for short periods of time before moving on to the next word.

They just are, for lack of a better description.

Either random or determined but by no free will of my own.

Words for me too. I never see pictures or anything of the sort. Always myself telling myself what I've thought... which does not seem like the most efficient way to go about it, but there you have it.

usually audio...............................................sometimes with text

When I read, like a novel or something, it’s a voice; usually my own, but sometimes with an accent or tone that matches how I perceive the character or narrator.

When I think, or meditate, it’s usually always my own voice, never actually visual words unless I am picturing how to spell a word. I often times think before I say something, which frustrates my peers. It appears that I am a slow speaker, but really I just want to make sure that what comes out of my mouth is something I wouldn't want to 'take back.'

When I visualize objects or structures, the images manifest themselves as a brownish red in color and with increased detail the more I focus on particular aspects of the image. Color is added if my brain indicates that I desire it.

Visualizing nature, in its marvelous splendor, is rich with color the moment of manifestation and often times with many sounds and movements of the life and elements.

Thoughts enter with your own mind and you can encompass multiple thoughts, too.