Some embodiments of the invention provide a novel method for recognizing characters that are input through touch strokes on a touch-sensitive sensor (e.g., a touch-sensitive display screen or a touch-sensitive surface) of a device (e.g., a mobile device, a remote control, a trackpad, etc.). In some embodiments, the sensor has a space-constrained area for receiving the touch input. In some embodiments, the method places no limitations on where the user can write in the space provided by the device. As such, successive characters might not follow each other in the space. In fact, later characters might overlap earlier characters or they might appear before earlier characters.