Imperatives

Imperatives in English do not require overt subjects. The subject in imperatives is second person, i.e. you, whether it is overt or not, as is clear from the verbal agreement and the interpretation. Imperatives with overt subjects can be parsed using the trees already needed for declaratives. The imperative cases in which the subject is not overt are handled by the imperative trees discussed in this section. The imperative trees in English XTAG grammar are identical to the declarative tree except that the NP₀ subject position is filled by an $\epsilon$, the NP₀ <agr pers> feature is set in the tree to the value 2nd and the <mode> feature on the root node has the value imp. The value for <agr pers> is hardwired into the epsilon node and insures the proper verbal agreement for an imperative. The <mode> value of imp on the root node is recognized as a valid mode for a matrix clause. The imp value for <mode> also allows imperatives to be blocked from appearing as embedded clauses. Figure 16.1 is the imperative tree for the transitive tree family.

   

Figure: Transitive imperative tree: $\alpha$Inx0Vnx1