An example process includes: receiving a natural language input having a start time and including first and second portions respectively received from the start time to a first time and from the start time to a second time after the first time; determining an end time of the natural language input; executing, at least partially between the first time and the end time, a first task flow based on the first portion, including: obtaining a first executable object representing a first candidate action; executing, at least partially between the second time and the end time, a second task flow based on the second portion, including: obtaining a second executable object representing a second candidate action; in response to determining the end time, selecting a candidate action from a plurality of candidate actions each represented by a respective executable object; and executing the respective executable object representing the selected candidate action.