A method of building a mixed-initiative grammar can include receiving one or more conjoin phrases, wherein each conjoin phrase is associated with a selected one of the plurality of directed dialog grammars, and receiving a user input specifying a selected grammar generation technique. The mixed-initiative grammar can be automatically generated, in accordance with the selected grammar generation technique, such that the mixed-initiative grammar specifies an allowable ordering of sets when interpreting a user spoken utterance and whether duplicative phrases are allowable within the user spoken utterance.