18. The non-transitory computer storage media of claim 15 , wherein: identifying, using the event model, one or more current or future events related to the user that are relevant to the action comprises: identifying user data from the event model that is potentially relevant to the action; determining a level of confidence for an association of the one or more potentially relevant current or future events from the identified user data and the context of the voice input; and identifying one or more current or future events related to the user that are relevant to the action from the potentially relevant events based on the determined level of confidence.
18. The non-transitory computer storage media of claim 15 , wherein: identifying, using the event model, one or more current or future events related to the user that are relevant to the action comprises: identifying user data from the event model that is potentially relevant to the action; determining a level of confidence for an association of the one or more potentially relevant current or future events from the identified user data and the context of the voice input; and identifying one or more current or future events related to the user that are relevant to the action from the potentially relevant events based on the determined level of confidence. 19. The non-transitory computer storage media of claim 18 , the operations further comprising, when the level of confidence is sufficiently low, presenting a refining prompt to allow the user to select one or more possible values for the one or more missing parameters, the one or more possible values being determined based on data associated with the one or more current or future events.