Interrogative Reformulation Patterns and Acquisition of Question Paraphrases

We describe a set of paraphrase patterns for questions which we derived from a corpus of questions, and report the result of using them in the automatic recognition of question paraphrases. The aim of our paraphrase patterns is to factor out different syntactic variations of interrogative words, since the interrogative part of a question adds a syntactic superstructure on the sentence part (i.e., the rest of the question), thereby making it difficult for an automatic system to analyze the question. The patterns we derived are rules which map surface syntactic structures to semantic case frames, which serve as the canonical representation of questions. We also describe the process in which we acquired question paraphrases, which we used as the test data. The results obtained by using the patterns in paraphrase recognition were quite promising.