1. A method performed by system of one or more data processing devices, the method comprising: receiving, at the system, information characterizing a first user interaction with a touchscreen; receiving, at the system, information characterizing a second user interaction with the touchscreen; the system assigning a probability to each of two or more interpretations of a combination of the first user interaction and the second user interaction, each of the interpretations construing the combination as a different pair of characters, each of the probabilities embodying a likelihood that the first user interaction and the second user interaction represent the respective pair of characters; the system using the two or more interpretations to search a collection of data for objects that are each identifiable by one of the two or more interpretations; and the system outputting identifiers of at least some of the objects.