Lexical Semantics

What is word meaning?

• In terms of other words: lexical relations
• In terms of semantic primitives, via decomposition
• In terms of perception, action, and emotion
• No such thing
• Knowledge of words vs. knowledge of the world
• Context dependence

What we need word meaning for

• Inference
  • A is bigger than B. Which is smaller, A or B?
  • Which is smaller, this or that?
• Finding a referent: Hand me the chisel.
• Generation: Describe this.

Approaches

• Lexical relations
  • Synonymy, antonymy, part-whole, type-token (isa)
  • Positive and negative concepts: Tuesday `the day after Monday and before Wednesday', Gentile `not Jewish', hammer `used to hit nails'
  • WordNet (Beckwith et al.)
    • Nouns
      • Hyponymy/hypernymy
      • Meronymy/holonymy (components, members, stuff)
      • Antonymy
    • Adjectives
      • Antonymy
      • "Pertainymy" (electrical)
    • Verbs
      • 15 semantic domains (motion, change, perception, contact, creation, possession, communication, competition, emotion, cognition, social interaction, body, weather; statives; catenatives (prevent, succeed, dare)); "troponymy" (manner of; stroll/walk)
      • Antonymy: manner (shout/whisper), spatial (rise/fall), opposing states (live/die), resulting in opposing states (soften/harden), reversal (button/unbutton)
      • Meronymy(?): script-like activities
      • "Entailment": drive/ride, snore/sleep, succeed/try, dent/hit
      • Pointers to nouns: throw/pottery
• Definitions, conditions
  • Necessary conditions, inherent features; analysis
  • Sufficient conditions: generation
  • Centrality conditions: focal value for continuously varying attributes
  • Typicality conditions, preference rules: GAMES involve COMPETITION, TIGERS have STRIPES
• Decomposition, semantic primitives
  • Verb meanings: conceptual dependency (primitive acts)
  • Noun taxonomies
• Metaphor, understanding one domain in terms of another
  • Gruber, Jackendoff, etc.: localism, all events and states in relation to spatial location and motion
  • Lakoff: ANGER is HEAT, MARRIAGE is WAR
• Prototypes (Rosch, etc.): concepts as typical instances or combinations of typical features
• Radial categories (Lakoff)
• Co-occurrence "semantics": using statistical properties of words to cluster them in semantic categories
• Connectionist nets that ground lexical semantics in perception

[L645 Syllabus]