Abstract: A user interface system and method are disclosed. The system comprises a controller, a data repository and an I/O unit. The user interface system is configured to cause, via the I/O unit, a user interface device of a user to provide a stimulus to the user, the user interface system is further configured to receive, from the user, data on the stimulus. In response to the stimulus and the data provided by the user on the stimulus, the user interface system is arranged to record, in the data repository, stimulus recognized by the user. The controller is operable to determine an optimized set of stimuli to be used by the user interface device in dependence on the stimuli recognized by the user, the optimized set matching the number of stimuli provided by the user interface device. The controller being arranged to communicate with the user interface device and configure the user interface device to use the optimized set of stimuli for its functions.