Natural Language Interface Gems

Edgar F. Codd
Robert S. Arnold
Jean-Marc Cadiou
Chin-Liang Chang
Nick Roussopoulos


1974 - 1977, Edgar F. Codd, Robert S. Arnold, Jean-Marc Cadiou, Chin-Liang Chang, Nick Roussopoulos (IBM)

An explanation of the name

To rendezvous (i.e. "meet") with the casual user

This is a gem, because

Created by the inventor of the relational database, E.F. Codd, this system was designed to meet the quirks of the casual user as much as possible. The user was allowed to enter one or more sentences, or sentence-parts. He or she was allowed to make mistakes and add and change the restrictions of the question later. The system had a very extended clarification dialog aimed to make sure that the system understood exactly what the user meant. For the same reason, it had extensive support for paraphrasing the generated knowledge base query so as to be comprehensible to the user. In contrast to other systems, this system does not parse the user's sentence into a parse tree. In stead, using conditional rules, patterns of words were interpreted directly as parts of a relational query.


Programming language
Natural language
Type of analysis
Language constructs
Noun Phrases, Verb Phrases, Preposition Phrases, ADJective Phrases, Negations

Data flow

Natural Language input
"Word normalizer"
  • Lexicon lookup
  • Morphological analysis
  • Open-ended token recognition
  • Proper names lookup in knowledge base
  • Semantic composition
    (production rules)
  • Nominal compounds
  • Semantic conflict detection
  • Anaphora resolution
Knowledge source form
  • Handle aggregations
    Knowledge base answers
    • Spelling correction
    • Cooperative responses
    • Paraphrase knowledge base query
    Natural Language output