10. A system for displaying electronic text and controlling playback of a soundtrack synchronized to the reading speed of a user comprising: a display configured to display the electronic text; a user interface configured to receive user input to control the system; an audio output system that is operable to generate audio output for the user to hear; an electronic text display module configured to process electronic text data representing the electronic text and control display of the electronic text on the display in response to user input from the user interface; a soundtrack playback module configured to: generate a reading position counter corresponding to an estimated current text position indicative of a word in the electronic text that the user is currently reading, the reading position counter incrementing at a rate based at least partly on a configurable user reading speed variable representing the user's reading speed; and process soundtrack data representing the soundtrack to control playback of the soundtrack over the audio output system, the soundtrack data defining multiple audio regions for the soundtrack, each audio region being defined by audio data comprising: an audio track for playback in the audio region; a start text position indicative of the word in the electronic text corresponding to where playback of the audio region is to begin; and a stop text position indicative of the word in the electronic text corresponding to where the playback of the audio region is to cease; wherein the soundtrack playback module is configured to coordinate playback of the audio track for the audio region based on the reading position counter to synchronize playback of the audio regions of the soundtrack with the user's reading of the electronic text; and a reading speed detector that is configured to: track a movement of at least one eye of the user with an eye tracker to detect at least one of a predetermined type of eye movements; determine the user's reading scan rate based on the detected type of eye movements and a timer, the reading scan rate being a value indicative of a number of eye movements per unit time without requiring detection of an exact position of a user's gaze within the electronic text; and calculate an estimate of the user's reading speed based on the determined reading scan rate and supplementary scan rate data relating to the electronic text and/or user that is indicative of an actual or average quantity of electronic text per type of detected eye movement, wherein the soundtrack playback module is configured to update the user reading speed variable at least partly based on the estimate of the user's reading speed as calculated by the reading speed detector.
10. A system for displaying electronic text and controlling playback of a soundtrack synchronized to the reading speed of a user comprising: a display configured to display the electronic text; a user interface configured to receive user input to control the system; an audio output system that is operable to generate audio output for the user to hear; an electronic text display module configured to process electronic text data representing the electronic text and control display of the electronic text on the display in response to user input from the user interface; a soundtrack playback module configured to: generate a reading position counter corresponding to an estimated current text position indicative of a word in the electronic text that the user is currently reading, the reading position counter incrementing at a rate based at least partly on a configurable user reading speed variable representing the user's reading speed; and process soundtrack data representing the soundtrack to control playback of the soundtrack over the audio output system, the soundtrack data defining multiple audio regions for the soundtrack, each audio region being defined by audio data comprising: an audio track for playback in the audio region; a start text position indicative of the word in the electronic text corresponding to where playback of the audio region is to begin; and a stop text position indicative of the word in the electronic text corresponding to where the playback of the audio region is to cease; wherein the soundtrack playback module is configured to coordinate playback of the audio track for the audio region based on the reading position counter to synchronize playback of the audio regions of the soundtrack with the user's reading of the electronic text; and a reading speed detector that is configured to: track a movement of at least one eye of the user with an eye tracker to detect at least one of a predetermined type of eye movements; determine the user's reading scan rate based on the detected type of eye movements and a timer, the reading scan rate being a value indicative of a number of eye movements per unit time without requiring detection of an exact position of a user's gaze within the electronic text; and calculate an estimate of the user's reading speed based on the determined reading scan rate and supplementary scan rate data relating to the electronic text and/or user that is indicative of an actual or average quantity of electronic text per type of detected eye movement, wherein the soundtrack playback module is configured to update the user reading speed variable at least partly based on the estimate of the user's reading speed as calculated by the reading speed detector. 15. The system according to claim 10 wherein the reading scan rate is a page turn rate and the reading speed detector is configured to: initiate a timer when the user turns to a new page of the electronic text; processing, subsequent to initiating the timer, the movement of at least one eye from the eye tracker to detect a page change eye movement by detecting eye movements, the page change eye movement indicative of the user changing the reading position in the electronic text from an end of a current page of the electronic text to the start of a next page of electronic text; and calculate an estimate of the user's reading speed based on supplementary scan rate data indicative of the quantity of electronic text on the page and the value of the timer at the detected page change eye movement.