• Use background knowledge to disambiguate between similar sounding statements with different meanings

Thematic Role Systems


"Ashok made pancakes for David with a griddle."

Lexical analysis

  • categorize words, noun, verb, etc
    • "Ashok (noun) made (verb) pancakes for David with a griddle."
  • noun phrase and verb phrase encompassing multiple words
    • "Ashok(noun phrase) | made pancakes for David with a griddle(verb phrase)"

Semantic analysis

  • structure of the sentence like action, object, beneficiary and instrument
    • "Ashok(agent) made(verb) pancakes(thematic object) for David(beneficiary) with a griddle(instrument)."
  • Frame representation
Thematic Role:
- Verb: make
- Agent: Ashok
- Beneficiary: David
- Thematic Object: Pancakes
- Instrument: Griddle
  • capture verbs
  • Single verbs can be ambiguous

Leveraging Constraints


Constraints imposed by the language help guide meaning

PrepositionThematic Roles
byAgent, conveyance, location
forBeneficiary, duration
withCoagent, instrument

Examples of by:

  • "That was written by Ashok" - Agent
  • "David went to NY by train" - Conveyance
  • "David stood by the statue" - Location

Individual verbs can be ambiguous

!!! 14.09 resolving ambiguity in verbs