Understanding
- Use background knowledge to disambiguate between similar sounding statements with different meanings
Thematic Role Systems
Analysis
"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
Constraints imposed by the language help guide meaning
| Preposition | Thematic Roles |
|---|
| by | Agent, conveyance, location |
| for | Beneficiary, duration |
| from | Source |
| to | Destination |
| with | Coagent, 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