1. A method of operating an electronic device comprising the steps of: initiating entry of a content string; determining a most probable completion alternative using a personalized and learning database; displaying the most probable completion alternative; determining whether a user has accepted the most probable completion alternative; and adding the most probable completion alternative to the content string when the user has accepted the most probable completion alternative; wherein a user interface is provided that comprises a navigation key having a first set of controls and a second set of controls; wherein said first set of controls are configured for acceptance or non-acceptance of the most probable completion alternative currently displayed at the display when in an editing mode and said second set of controls are configured for changing or overriding the most probable completion alternative currently displayed at the display when in the editing mode; wherein said first of controls are configured for scrolling a cursor right one character at a time or scrolling the cursor left one character at a time when said first set of controls are in a navigation mode; wherein said second set of controls are configured for scrolling the cursor down one line at a time or scrolling the cursor up one line at a time, when said second set of controls are in the navigation mode; and wherein: a right control of said first set of controls is configured for, in navigation mode and in a hold and press mode, jumping the cursor to the right one word at a time; a left control of said first set of controls is configured for, in navigation mode and in the hold and press mode, jumping the cursor left one word at a time; the left control being further configured for, in editing mode and in the hold and press mode, dismissing prediction and locking a last key press entry.