DIAGRAM: a grammar for dialogues

ABSTRACT

An explanatory overview is given of DIAGRAM, a large and complex grammar used in an artificial intelligence system for interpreting English dialogue. DIAGRAM is an augmented phrase-structure grammar with rule procedures that allow phrases to inherit attributes from their constituents and to acquire attributes from the larger phrases in which they themselves are constituents. These attributes are used to set context-sensitive constraints on the acceptance of an analysis. Constraints can be imposed by conditions on dominance as well as by conditions on constituency. Rule procedures can also assign scores to an analysis to rate it as probable or unlikely. Less likely analyses can be ignored by the procedures that interpret the utterance. For every expression it analyzes, DIAGRAM provides an annotated description of the structure. The annotations supply important information for other parts of the system that interpret the expression in the context of a dialogue. Major design decisions are explained and illustrated. Some contrasts with transformational grammars are pointed out and problems that motivate a plan to use metarules in the future are discussed. (Metarules derive new rules from a set of base rules to achieve the kind of generality previously captured by transformational grammars but without having to perform transformations on syntactic analyses.)

REFERENCES

• 1: Becket, A.L., and Arms, D.G. Prepositions as predicates. In Papers from the 5th Regional Meeting of the Chicago Linguistic Society, Univ. Chicago, Chicago, IL., April 18-19, 1969.
• 2: Bresnan, J. A realistic transformational grammar. In Linguistic Theory and Psychological Reality, Halle, M., Bresnan, J., and Miller, G.A. (Eds.) MIT Press, Cambridge, MA., 1978.
• 3: Chafe, W.L. Givenness, constrastiveness, definiteness, subjects, topics, and point of view. In Subject and Topic, C.N. Li (Ed.) Academic Press, New York, 1976.
• 4: Culicover, P.W., Wasow, T., and Akmajian, A. (Eds.) Formal Syntax. Academic Press, New York, 1977.
• 5: Dresher, B.E., and Hornstein, N. Trace theory and NP movement rules. Linguistic Inquiry 10 (Winter 1979)65-82.
• 6: Gazdar, G. English as a context-free language. Manuscript, April 1979.
• 7: Gazdar, G., Pullum, G.K., and Sag, 1. A context-free phrasestructure grammar for the English auxiliary system. To appear.
• 8: Grosz, B. Focusing and description in natural language dialogues. In Elements of Discourse Understanding, A.K. Joshi et al. (Eds.) Cambridge Univ. Press, Cambridge, England, 1980.
• 9: Grosz, B., and Hendrix, G. A computational perspective on indefinite reference. Tech. Note 181, SRI International, Menlo Park, CA., 1980.
• 10: Hobbs, J., and Robinson, J. Why ask. Discourse Processes 2, 4 (Oct.-Dec. 1979) 311-318.
• 11: Jackendoff, R. Constraints on phrase-structure rules. In Culicover, P.W., Wasow, T., and Akmajian, A. (Eds.), Formal Syntax, Academic Press, New York, 1977, 249-283.
• 12: Jackendoff, R. X-Bar Syntax: A Study of Phrase Structure. MIT Press, Cambridge, MA, 1977.
• 13: Aravind K. Joshi , Leon S. Levy, Phrase structure trees bear more fruit than you would have thought, Proceedings of the 18th annual meeting on Association for Computational Linguistics, June 19-22, 1980, Philadelphia, Pennsylvania [doi>10.3115/981436.981451]
• 14: Kaplan, R.M., and Bresnan, J.W. Lexical-functional grammar: A formal system for grammatical representation. To appear in J.W. Bresnan (Ed.), The Mental Representation of Grammatical Relations. MIT Press, Cambridge, MA, 1980.
• 15: Kurt Konolige, Capturing linguistic generalizations with metarules in an annotated phrase-structure grammar, Proceedings of the 18th annual meeting on Association for Computational Linguistics, June 19-22, 1980, Philadelphia, Pennsylvania [doi>10.3115/981436.981452]
• 16: Langacker, R.W. The form and meaning of the English auxiliary. Language 54 (Dec. 1978), 853-882.
• 17: Paxton, W.H. The language definition system. In Understanding Spoken Language, D.E. Walker (Ed.) North-Holland, New York, 1978.
• 18: William Hamilton Paxton, A framework for speech understanding., 1977
• 19: Robinson, J. Dependency structures and transformational rules. Language 46 (June 1970), 259-285.
• 20: Robinson, A. Interpreting natural-language utterances in dialogs about tasks. Tech. Note 210, SRI International, Menlo Park, CA, March 15, 1980. (To appear.)
• 21: Ross, J.R. Adjectives as noun phrases. In Modern Studies in English, D.A. Reibel and S.A. Schane (Eds.) Prentice-Hall, Englewood Cliffs, N J, 1969.
• 22: Searle, J.R. A classification of illocutionary acts. In Proc. Texas Conf. Pefformatives, Presuppositions and 1mplicatures, Center for Applied Linguistics, Arlington, VA, 1977.
• 23: Tesnlere, L. Elements de Syntaxe Structurale, 2nd ed. Editions Klincksieck, Paris, France, 1976.
• 25: W. A. Woods, Transition network grammars for natural language analysis, Communications of the ACM, v.13 n.10, p.591-606, Oct. 1970 [doi>10.1145/355598.362773]

INDEX TERMS

Primary Classification:
  I. Computing Methodologies
  I.2 ARTIFICIAL INTELLIGENCE
      I.2.7 Natural Language Processing
          Subjects: Language parsing and understanding

Additional Classification:
  J. Computer Applications
  J.5 ARTS AND HUMANITIES
      Subjects: Language translation

General Terms:
Languages

Keywords:
annotations, attribute inheritance, augmented rules, contextual constraints, dialogue, likelihoods, metarules, phrase-structure grammar, transformations