I'm not convinced our minds are actually different in kind, as opposed to just having quality differences in how we perceive ourselves. We can run the experiment right now. Does anyone actually have an internal voice narrating the feeling you get watching a sunset?
At other times, when I’m in a relaxed and unfocused state, particularly in the shower, my inner voice goes in circles and explains the same thing over and over. This tends to happen when I find an explanation really logically satisfying or interesting. This is perhaps a less interesting situation than the last one, because going through an argument repeatedly to understand it better is probably something that everyone does. But when it goes in circles too many times, I get sick of the topic, and there’s a distinct sense of “will you just shut up already”. Then I have to actively come up with something else to think about.
In both situations, my inner voice is becoming slightly intrusive, acting like a distinct entity from my conscious focus; and it always comes in the form of words even if I’m not actively seeking words. I think that goes beyond just “do I know the words for what I’m thinking”.
Mine's not even normally restricted to being an inner voice. I live by myself, and I talk to myself out loud constantly. It's mostly just narration, but I think being explicit about things helps my executive function weaknesses.
"Alright, smeej. Up from the couch. Let's put the dishes away. Grab those two first. Then let's shower because it's getting kind of late this morning."
I catch myself muttering out loud in hardware stores (which are somehow less overwhelming than grocery stores), but who hasn't seen somebody looking for something and muttering to themselves? I'm just that person!
And then if you talk to yourself about everything, how do you think about things you can't talk about? When I imagine going to the store I can imagine all the different routes etc in a second, there is no way I can talk about the different routes in a second in an inner voice, so to me the inner voice seems utterly useless at best or it hurts your ability to think at worst.