21. A non-transitory computer-readable storage medium comprising computer-executable instructions, which when executed by one or more processors, cause the one or more processors to: detect a sequence of contact inputs via a keyboard interface on the touch-sensitive display, wherein detecting a contact input of the sequence of contact inputs comprises detecting an initiation of contact with the touch-sensitive display at a first position of the keyboard interface, a continuous contact motion from the first position to a second position of the keyboard interface, and a release of contact from the touch-sensitive display at the second position, and wherein the contact input represents a user selection of at most one character key of the keyboard interface; determine a plurality of candidate words corresponding to the sequence of contact inputs; rank the plurality of candidate words based on a probability that the contact input is an intended input to select a first key of the keyboard interface, and a probability that the contact input is an intended input to select a second key of the keyboard interface; and display a portion of the plurality of candidate words for user selection.
21. A non-transitory computer-readable storage medium comprising computer-executable instructions, which when executed by one or more processors, cause the one or more processors to: detect a sequence of contact inputs via a keyboard interface on the touch-sensitive display, wherein detecting a contact input of the sequence of contact inputs comprises detecting an initiation of contact with the touch-sensitive display at a first position of the keyboard interface, a continuous contact motion from the first position to a second position of the keyboard interface, and a release of contact from the touch-sensitive display at the second position, and wherein the contact input represents a user selection of at most one character key of the keyboard interface; determine a plurality of candidate words corresponding to the sequence of contact inputs; rank the plurality of candidate words based on a probability that the contact input is an intended input to select a first key of the keyboard interface, and a probability that the contact input is an intended input to select a second key of the keyboard interface; and display a portion of the plurality of candidate words for user selection. 23. The computer-readable storage medium of claim 21 , wherein: the probability that the contact input is an intended input to select the first key of the keyboard interface is determined based on a distance between the first position and a center position of the first key; and the probability that the contact input is an intended input to select the second key of the keyboard interface is determined based on a distance between the first position and a center position of the second key.