My mental experience is something like a voice that rapidly narrates my every thought at all times (and is indeed reading along with me as or slightly before I type this). Saying "narrates my every thought" is kind of a weird construction because those essentially are my thoughts not just narration. I also have what I think of as a separate thread that is barely at the edge of awareness and has thoughts that aren't quite words but more like feelings. There are no images of any kind that accompany any of this nor a black void on which images might be rendered.

In another comment I likened it to reading a book. When I read a book that voice is just enunciating the stream of text instead of my thoughts (except when I get distracted and the internal voice starts narrating my thoughts again).

So, for contrast, my mental experience is mainly visual with some other constructed senses, and intermittent verbalizations. Sometimes the verbalizations are sentences. Sometimes they're phrases, or single words. Sometimes they're entirely absent.

Sometimes my mental experience is something I might call spatializations, rather than visualizations, especially when I'm solving problems with data structures. These will be 3-dimensional spatial arrangements of symbolic objects without any specific shapes, colors, or textures.

I've been a programmer and a technical writer for a little over thirty years. I have a lot of practice converting my thoughts into words. It's pretty much always a distinct conversion process, though. I usually cannot speak my thoughts because they mostly aren't words. I have to go through a process of translation to represent them as words.