I remember reading it in something semi academic many, many years ago, so you'll have to google it. I think it was linked to dyslexia and languages with spelli

I remember reading it in something semi academic many, many years ago, so you'll have to google it. I think it was linked to dyslexia and languages with spelling and maybe japanese, and how china simplified it's characters led to higher literacy, although that might have a few confounding variables.