When I was a kid a friend asked me, "Hey, you speak three languages. Which one do you think in?"
I was bemused, and thought... "people think in words?"
Apparently people with ADHD or Autism can develop the inner voice later in life.
In my 20s, language colonized my brain. Took me years of meditation to get some peace and quiet back...
Doesn't hellen keller provide a counterexample? She seemed to imply pretty strongly that before acquisition of language she operated more on stimulus and bodily perception rather than higher-level thought.
It's clear humans have several networks working together. Some Mathematicians report they 'see' the solution, these rely on a visual network *. Others report they prefer to do math symbolically (relying on the language network?).
Perhaps there are also multiple human paths to higher-level thought, with Keller (who lost her sight) using the language facility while others don't have to.
* Given Box 1 contents, the article authors seem unaware of the research on this? e.g.
https://www.youcubed.org/resource/visual-mathematics/
https://www.hilarispublisher.com/open-access/seeing-as-under...
Keller's early experience of the world differed from typical in dimensions beyond language recognition.
One could make the argument that higher-level thought is not the same as awareness of higher-level thought; perhaps language only affords the latter.
She learned "language" later than most. The primary function for her was as communication with the outside world, not for cognition, which she was already doing from birth.
Excellent, comprehensive, extremely thorough work behind all this. Maturana would love it!