1. A method for operating a digital assistant, the method comprising: at an electronic device having one or more processors and memory: receiving user speech input; generating a textual representation of the user speech input; parsing the textual representation to determine a primary domain representing a user intent for the textual representation; identifying a first substring from the textual representation that corresponds to a first attribute of the primary domain; parsing the identified first substring to determine a secondary domain representing a user intent for the first substring; and performing a task flow comprising one or more tasks based on the primary domain and the secondary domain.