We are limited by the speed of communication medium we use. If I have to talk to you I need to process my thoughts so I limited by the speed of processing my thoughts. Then I need to convert my thoughts to speech. So I am limited by the speed at which my brain can convert my thoughts to speech. Then I need to speak them out. So I am limited by the speed at which I can talk. Then you should hear and process it. So I am limited by the speed at which you can comprehend.

For this reason sometimes I feel that writing and reading is better. As on is not affected by the other. But since english is weird language and they way talk and write are different(non phonetic like say kannada or telugu) it introduces more constraints. Also though you don't need to know all the words to make sense of the sentence you should still read them or atleast skim through them. The same goes for the next level of granularity. You don't need to know all the letters of the word. What if we could identify only the relevant required parts and only highlight them. You can always go back to the skipped/skimmed part if you are having comprehending difficulties. It would greatly increase the rate of consumption of written text by leaps and bounds.

This is exactly what Bionic reading does. I am exploring this more now. DM me if you need more details.