11. A non-transitory computer-readable storage medium encoded with instructions that, when executed, cause at least one processor to: output, for display, a graphical keyboard comprising a plurality of keys; in response to detecting a first portion of a gesture at a presence-sensitive input device, generate a word prefix comprising a plurality of characters; in response to detecting, during the gesture, a second portion of the gesture at the presence-sensitive input device: update, based on a word in a dictionary, the word prefix to include an additional character; responsive to determining that an alignment score of the gesture matching the word prefix with the additional character does not satisfy a threshold, determine, using correction data that indicates at least one alternative word prefix that is based at least in part on a misspelling of the word in the dictionary, an alternative alignment score, wherein the alternative word prefix comprises at least a portion of the word prefix; determine, based on the alternative alignment score for the alternative word prefix, a candidate word; and output, for display, the candidate word.
11. A non-transitory computer-readable storage medium encoded with instructions that, when executed, cause at least one processor to: output, for display, a graphical keyboard comprising a plurality of keys; in response to detecting a first portion of a gesture at a presence-sensitive input device, generate a word prefix comprising a plurality of characters; in response to detecting, during the gesture, a second portion of the gesture at the presence-sensitive input device: update, based on a word in a dictionary, the word prefix to include an additional character; responsive to determining that an alignment score of the gesture matching the word prefix with the additional character does not satisfy a threshold, determine, using correction data that indicates at least one alternative word prefix that is based at least in part on a misspelling of the word in the dictionary, an alternative alignment score, wherein the alternative word prefix comprises at least a portion of the word prefix; determine, based on the alternative alignment score for the alternative word prefix, a candidate word; and output, for display, the candidate word. 15. The non-transitory computer-readable storage medium of claim 11 , comprising instructions that, when executed, cause the at least one processor of the computing device to: determine a transposition of a substring of the word prefix, wherein character positions of at least two characters of the substring are transposed in the transposition; and generate the alternative word prefix comprising at least the transposition.