Grammatically-based automatic word class formation

Lynette Hirschman, Ralph Grishman, Naomi Sager

Research output: Contribution to journalArticlepeer-review


Most previous attempts at producing word classes (thesauri) by statistical analysis have used very limited distributional information such as word co-occurrence in a document or a sentence. This paper describes an automatic procedure which uses the syntactic relations as the basis for grouping words into classes. It forms classes by grouping together nouns that occur as subject (or object) of the same verbs, and similarly by grouping together verbs occurring with the same subject or object. The program was applied to a small corpus of sentences in a subfield of pharmacology. This procedure yielded the word classes for the subfield, in good agreement with the word classes recognized by pharmacologists. The word classes can be used to describe the informational patterns that occur in texts of the subfield, to disambiguate parses of a sentence, and perhaps to improve the performance of current information retrieval systems.

Original languageEnglish (US)
Pages (from-to)39-57
Number of pages19
JournalInformation Processing and Management
Issue number1-2
StatePublished - Jun 1975

ASJC Scopus subject areas

  • Information Systems
  • Media Technology
  • Computer Science Applications
  • Management Science and Operations Research
  • Library and Information Sciences


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