Psycholinguistics research shows that the human brain processes words as single units, and that not all characters that make up words are actually read.
Therefore, the actual reading speed of a human being is calculated in words per minute (WPM). In other words, it's actually the WPM, not the characters per second (CPS), that tells us if a subtitle is too fast to be read. Is it possible to add a WPM count feature for each subtitle line in Aegisub?
I think that allowing the user to choose to display the WPM count in addition to/instead of the CPS would be a great addition to an already software, since this feature would provide the user with a more sensible indicator of the readability of his/her subtitles