1. A computer-implemented method, comprising: receiving, at a computing system, audio data that indicates a voice input that was provided to a computing device; receiving, at the computing system, display data that characterizes an interface that was displayed on a screen of the computing device when the voice input was provided to the computing device; determining, by the computing system and based at least on the display data that characterizes the interface that was displayed on the screen of the computing device when the voice input was provided to the computing device, a particular dialog state, from among a plurality of dialog states, that corresponds to the voice input; identifying a set of n-grams that are associated with the particular dialog state that corresponds to the voice input, wherein the set of n-grams are associated with the particular dialog state based at least on n-grams in the set of n-grams occurring frequently in historical voice inputs that correspond to the dialog state; in response to identifying the set of n-grams that are associated with the particular dialog state that corresponds to the voice input, biasing a language model by adjusting probability scores that the language model indicates for n-grams in the set of n-grams; and transcribing the voice input using the adjusted language model.