It seems Game.TextReadingSpeed is not complying.
Game.TextReadingSpeed = 9; // makes no difference to time on screen.
Build 3.4.0.16
Edit: Just realised I am using the Phylactere Module :-[
Perhaps Snarky's SpeechBubble (http://www.adventuregamestudio.co.uk/forums/index.php?topic=55542.0) module is complying to Game.TextReadingSpeed?
It is 8-)
The Phylactere Module has it's own Text reading speed....