I don’t make a sound or word in my mind but I definitely keep track of the number. My thinking is definitely structured and there are things in my thoughts but there is no words or voice. I also can’t see images in my mind either. I’ve no idea what an inner monologue or the minds eye is like. I have however over the years found ways to produce these experiences in a way of my own. I found for instance some rough visualization was helpful in doing multi variate calculus but it’s very difficult and took a lot of practice. I’ve also been able to simulate language in my mind to help me practice difficult conversations but it’s really difficult and not distinct.
I would note though I have a really difficult time with arithmetic and mechanical tasks like counting. Mostly I just lose attention. Perhaps an inner voice would help if it became something that kept a continuity of thought.