1. A method, implemented by one or more computing devices, for generating intent output information, comprising: receiving input data, the input data comprising: a first set of linguistic items with known intent labels; and a second set of linguistic items without known intent labels; determining an intent for each linguistic item in the input data, to produce intent output information, by: if the linguistic item corresponds to a member of the first set, deterministically assigning an intent to the linguistic item based on a known intent label associated with the linguistic item; and if the linguistic item corresponds to a member of the second set, inferring the intent associated with the linguistic item based on selection log data, which reflects selections made by users in response to submitting linguistic items, the intent that is inferred being selected from a set of possible intents, including a first group of known intents associated with the known intent labels, and a second group of unknown intents, not represented by the known intent labels; and storing the intent output information in a data store, said receiving, determining, and storing being performed by said one or more computing devices.