11. A system comprising: one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising: receiving a sequence of strokes that represent a handwritten input; providing the sequence of strokes to both a delayed stroke handwriting recognizer and an overlapping handwriting recognizer, wherein a delayed stroke handwriting recognizer is a handwriting recognizer that orders strokes according to their respective horizontal spatial location before selecting one or more characters that correspond to the strokes, wherein an overlapping handwriting recognizer is a handwriting recognizer that does not reorder strokes according to their respective horizontal spatial location before selecting one or more characters that correspond to the strokes; receiving, from each of the delayed stroke handwriting recognizer and the overlapping handwriting recognizer, (i) a set of one or more candidate letters that the handwriting recognizer has selected as corresponding to the sequence of strokes, and (ii) a confidence score associated with the selection; and selecting, from among the set of candidate letters from the delayed stroke handwriting recognizer and the set of candidate letters from the overlapping handwriting recognizer, a particular set of candidate letters based on the confidence scores.
11. A system comprising: one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising: receiving a sequence of strokes that represent a handwritten input; providing the sequence of strokes to both a delayed stroke handwriting recognizer and an overlapping handwriting recognizer, wherein a delayed stroke handwriting recognizer is a handwriting recognizer that orders strokes according to their respective horizontal spatial location before selecting one or more characters that correspond to the strokes, wherein an overlapping handwriting recognizer is a handwriting recognizer that does not reorder strokes according to their respective horizontal spatial location before selecting one or more characters that correspond to the strokes; receiving, from each of the delayed stroke handwriting recognizer and the overlapping handwriting recognizer, (i) a set of one or more candidate letters that the handwriting recognizer has selected as corresponding to the sequence of strokes, and (ii) a confidence score associated with the selection; and selecting, from among the set of candidate letters from the delayed stroke handwriting recognizer and the set of candidate letters from the overlapping handwriting recognizer, a particular set of candidate letters based on the confidence scores. 17. The system of claim 11 , wherein the overlapping handwriting recognizer generates the confidence score based on a portion sequence of strokes that is based on a period of time, positional information, and previously received sequence of strokes.