Could anyone explain the rationale behind it? It seems that how we represent the letters and the words has significant impacts on how easily our brains digest t

Could anyone explain the rationale behind it? It seems that how we represent the letters and the words has significant impacts on how easily our brains digest them. Also a bit of tangent, but I wonder, could fellow English native speakers generally skim books like less than three to five seconds on each page, and roughly get the idea of those pages? I'm a native speaker of Chinese and it's pretty easy for me to do it in Chinese, but there's no way for me to do the same in English despite I've been reading English for years.