1. A method for entering a string of symbols, the method comprising: generating for display a sequence of symbols arranged in a row, wherein the symbols are grouped in groupings; monitoring user navigation between the groupings of symbols; determining a navigation pace based on the monitored user navigation, the navigation pace representing an interval of time taken by the user to navigate from a first grouping of symbols to a second grouping of symbols; receiving a user input to navigate to a third grouping of symbols; and selecting symbols for the third grouping of symbols based on the determined navigation pace in response to receiving the user input.
19. The method of claim 1 , further comprising: associating the first grouping of symbols with a first cluster, wherein the first cluster is generated for display on a display device; associating the second grouping of symbols with a second cluster, wherein the second cluster is generated for display on the display device simultaneously with the first cluster; receiving a first user input to move a highlight region to the first cluster; receiving a second user input to move the highlight region to the second cluster from the first cluster while the first cluster remains generated for display; and determining the navigation pace based on the interval of time between receipt of the first user input and the receipt of the second user input.