And I'd argue that if books did have syntax highlighting, parts of speech wouldn't be the best way to inflect it anyway. Maybe give a colour to each each charac

And I'd argue that if books did have syntax highlighting, parts of speech wouldn't be the best way to inflect it anyway. Maybe give a colour to each each character, or each location, or even just the subject of a sentence. Which "her" does this refer to? Which speaker is this? These are all potentially valuable things. And some books do do these things. Often thoughts are italic whereas spoken words are quoted. Pratchett puts Death's words in all caps.