It sometimes takes me 3 times longer to read something than other people. I’ve got no problem understanding it, no issue of intelligence, it’s a specific learning disability. it’s so incredibly frustrating when there is no button prompt and they take the message off so quickly.
tremault, via destructoid

In addition to low reading age being extremely common (14% of adults have a reading age of below 11 years), distraction can be an issue for all gamers, sometimes resulting in key information being missed. As reading speeds and ability are so varied even within very specific age brackets, it is not possible to set a speed for text to be displayed which will be appropriate for all readers.

Instead of a timer, dismiss information on a player action, allowing it to be stepped through. If that’s not possible, allow it to to be replayed or paused. If developing a chat system, allow messages to be browsed back through without automatically jumping focus back to a new message when it appears. Any of those methods remove the requirement for players to have a specific reading speed and constantly maintained attention.

Best practice example: Doom
Best practice example: Guacamelee!
Best practice example: Happy Wars
Best practice example: Awakening: The Dreamless Castle
Best practice example: Zelda: The Ocarina of Time