Methods, systems, and computer readable storage medium related to operating an intelligent automated assistant are disclosed. A user request is received through a conversation interface of the intelligent automated assistant, the user request including at least a speech input received from a user. One or more candidate domains relevant to the user request are identified from a plurality of predefined domains, where each predefined domain presents a respective area of service offered by the intelligent automated assistant, and the identifying is based on respective degrees of match between words derived from the user request and words representing vocabulary and entities associated with each predefined domain. Feedback is provided to the user through the conversation interface of the intelligent automated assistant, where the feedback presents a paraphrase of the user request and elicits additional input from the user to specify one or more parameters associated with a particular candidate domain.