Word Meaning
• Reference vs. Sense
• Meaning relationships
– Synonymy
– Antonymy
– Hyponymy
Sentence Meaning
• What do you know when you know what a
sentence means?
• => The conditions under which that
sentence would be true
Truth Conditions
• “World War II ended in 1945.”
• …is true if WWII did in fact end in 1945.
Truth Values
• “World War II ended in 1945.”
=T
• “World War II ended in 1919.”
=F
• What about:
• “Puli is a city in Taiwan.”
• We can understand this sentence because
we know its truth conditions.
• ‘I want to be the president of the U.S.’
vs.
‘I want to be George W. Bush.’
=> Different truth conditions
Principle of Compositionality
Meaning of a sentence
Meanings of its component parts (the words)
Plus
Structures they occur in (the relationships
between the words based on the syntax).
Sentential Meaning
S
– NP
– |
– Sandy
VP
|
runs
Truth Conditions
• The individual ‘Sandy’
• The set of runners
• => Is Sandy a member of the set of
runners?
Not just meanings of words
S
– NP
– |
– Dogs
–
VP
V
chase
NP
cats
Same words, different meanings
S
– NP
– |
– Cats
–
VP
V
chase
NP
dogs
Thematic Roles
• S => NP1 (Aux) VP
• VP => V NP2
• Agent: initiator of the action, capable of
volition
•
•
David broke the window.
The fox jumped up.
• Patient: undergo the effect of some action,
often undergo a change of state
• Fred shattered the rock.
• The sun melted the ice.
• Theme: moved by an action, or entity whose
location is described
• Fred threw the rock.
• The book is in the library.
• Dogs chase cats.
• => dogs = Agent; cats = Theme
• Cats chase dogs.
• => cats = Agent; dogs = Theme
• Dogs chase cats. (Active)
• Cats are chased by dogs. (Passive)
• Active sentence: Subject = Agent
• Passive sentence: Subject = Theme
Intersective Adjectives
• red book
»book
red
Subsective Adjectives
• snowflake
• big snowflake
• => Relative intersection
Semantic Relations between
Sentences
•
•
•
•
Entailment
If S1 is true, then S2 is also true.
S1:
Julius Ceasar was a famous man.
S2:
Julius Ceasar was a man.
• S1:
• S2:
Bob has a beagle.
Bob has a dog.
• => ‘beagle’ is a hyponym of ‘dog’.
Negative sentences
• Seattle is a hypernym of Ballard
• X: ‘Bill Gates doesn't live in Seattle.’
entails
• Y: ‘Bill Gates doesn't live in Ballard.’
Factive Verbs
• I know that Bob is in Spain.
• => Bob is in Spain.
• I regret the incident.
• => There was an incident.