Your comment seems like a non sequitur.
So in the same sense that I can use math without it being central to my thinking, it doesn't seem hard to believe that others can use language without it being central to their thinking.
Personally I've tried to become less dependent on language for thought, because I noticed I kept getting stuck on how to verbalize some thoughts even when there was no real need to. I think it's had an effect but it's hard to tell if I'm just imagining it or if imagining it is precisely the point (and I still get stuck on how to explain stuff in some imaginary context, but I suppose that's progress?)
My best guess is that an internal monologue may simply be an intermediate step as we internalize speech into our thoughts, so the need to keep verbalizing thought could eventually reduce, but it's hard to notice these kinds of changes in yourself because the skills don't disappear they just become something else.
I call it mental-ese. To talk i often first have to translate between it and my native language (English). obviously, it's by its very nature hard to express in words exactly what mental-ese consists of, and it might arguably be impossible in the same way we cannot express general qualia using the written language.
but I've heard enough similarities from others trying to express such to be convinced there's something there. surely the phrase "I can't express my thoughts in words" is common and has meaning to you?
The analogies I've heard commonly from myself and others to describe it is that I see/feel the shape of relationship between the concepts or abstract thoughts before I then try to put it into language. just as my other senses do not require written language to first describe (my experience of tasting a strawberry is something qualitatively different experienced/impressed on the mind, not a word).
Another analogy I've used to try to convey my apparent experience to others in contrast to many people is that it appears to me that a common way of experiencing the world is to have relative primacy or weight on "things"(words) and then people have to work towards the relationships between things. whereas I feel my mind works the other way, receiving impressions of relationships between or behind things first, such that they are the primary unit, and the words/things must then be built up from these.