Swype is a touch sensitive keyboard system for Android phones and tablets. It takes advantage of the layout of QWERTY keyboards. The QWERTY keyboard was laid out long ago so that the hammers which pressed the letters through the ink ribbon and into a typewriter and did not jam. Earlier versions of typewriters frequently jammed as people typed faster and faster. The QWERTY keyboard was designed so that letters which were infrequently used next to each other in words, were next to each other on the keyboard. This meant that the hammers which were triggered by each key press were not next to each other either and there was much less chance of them jamming together. The QWERTY keyboard caught on and the entire English speaking world uses it today.
Fast forward to the touchscreen. Suddenly people are tapping virtual keys on a flat screen but still with the QWERTY layout. It has the advantage that no extra keyboard is required and the screen can easily flip between different keyboards. However, it is slow and cumbersome at best.
Enter Swype. Swype takes advantage of the fact that the letters which most often lie next to each other in words are actually far apart on a keyboard. This means that tracing a line between them produces a fairly definitive shape. These shapes can be recognised to correspond with known words and new words can be learnt by the system. If this sounds complicated, then you have not used it yet. It is remarkably easy to pick up: