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CS182
Leon Barrett
with slides inspired by Eva Mok and Joe Makin
April 25, 2008
Announcements
• a9 out, due Thursday
• BBS articles are assigned for the final paper!
Schedule
• Last Week– Metaphor understanding using KARMA
– Grammars and parsing
• This Week– Construction Grammar, ECG
– Grammar Learning
• Next Week– ECG Learning
Questions
• What are constructions?
• How does ECG use constructions?
• Why is learning language hard?
• What is the poverty of the stimulus?
• What is Gold's Theorem?
Embodied constructions
construction HARRYform : /hEriy/meaning : Harry
construction CAFEform : /khaefej/meaning : Cafe
Harry
CAFEcafe
ECG NotationForm Meaning
Constructions have form and meaning poles that are subject to type constraints.
Questions
• What are constructions?
• How does ECG use constructions?
• Why is learning language hard?
• What is the poverty of the stimulus?
• What is Gold's Theorem?
A schema hierarchy of objects (Nomi)
schema Referentsubcase of Entityroles
categorydistributionboundednessnumbergenderaccessibilityresolvedref
schema Object subcase of Entity
schema Entity
schema Place
schema PhysicalObjectsubcase of Object, Place
schema Animate subcase of PhysicalObjectroles
animacyconstraints
animacy true←
schema Humansubcase of Animateroles
sexschema Nomi
subcase of Humansex female←
schema ManipulableObject subcase of PhysicalObject
schema Toysubcase of
ManipulableObjectschema Ball
subcase of Toy
slot filler
schema Cup subcase of ManipulableObject
The schemas we just defined
Entity Place
Object
PhysicalObject
Referent
AnimateManipulableObject
HumanToy
Nomi Mother FatherBook
Cup
Ball Block
Food
Doll Bed
Cake Juice
A schema hierarchy of actions (Nomi)
schema DirectedActionsubcase of Actionroles
patient : Entity
schema Actionroles
agent : Entity
schema Move subcase of Actionroles
mover : Entitydirection : Place
schema CauseMove subcase of DirectedAction, Moveroles
causer : Humanmover : PhysicalObjectmotion : Move
constraints motion.mover mover↔
motion.agent causer↔
motion.direction direction↔
agent causer↔
patient mover↔
identification constraint
type constraint
The schemas we just definedAction
Directed Action
CauseMove
Move
JointMoveTransfer
Constructions, finally (Nomi)construction RefExpr
form : SchematicFormmeaning : Referent
construction NomiCnlevel 0subcase of RefExprform : Word
self.f.orth "Nomi"←
meaningevokes Nomi as nself.m.category n↔
self.m.resolvedref n↔
local name
fancy way of sayingthat the category ofthe referent is Nomi
construction CupCnlevel 0subcase of RefExprform : Word
self.f.orth “cup"←
meaningevokes Cup as nself.m.category n↔
self.m.resolvedref n↔
Constructions, finally (Nomi)
construction CauseMotionVerbsubcase of MotionVerbmeaning : CauseMove
construction MotionVerbmeaning : Move
construction GetCnlevel 0subcase of CauseMotionVerbform : Word
self.f.orth "get"←
lexical construction
Constructions, finally (Nomi)
construction TransitiveCnlevel 2constructional
constituentsagt : RefExprv : CauseMotionVerbobj : RefExpr
formagt.f before v.fv.f before obj.f
meaningv.m.agent agt.m.resolvedref↔
v.m.patient obj.m.resolvedref↔
smaller constructions that it takes
ordering constraints on the constituents
Questions
• What are constructions?
• How does ECG use constructions?
• Why is learning language hard?
• What is the poverty of the stimulus?
• What is Gold's Theorem?
Difficulty of learning language
• What makes learning language difficult?– How many sentences do children hear?
– How often are those sentences even correct?
– Even when they're correct, how often are they complete?
– How often are children corrected when saying something wrong?
– How many possible languages are there?
Larger context
• War!– Is language innate?
– Covered in book
Questions
• What are constructions?
• How does ECG use constructions?
• Why is learning language hard?
• What is the poverty of the stimulus?
• What is Gold's Theorem?
Poverty and Opulence
• Poverty of the stimulus– Coined to suggest how little information children have to
learn from
• Opulence of the substrate– Opulence = “richness”
– Coined in response to suggest how much background information children have
Questions
• What are constructions?
• How does ECG use constructions?
• Why is learning language hard?
• What is the poverty of the stimulus?
• What is Gold's Theorem?
Gold's Theorem• Suppose that you have an infinite number of languages
– language = “set of legal sentences”
• Suppose that for every language Ln, there is a bigger language Ln+1
– makes every sentence, and then some
• There's some language Linfinity
– contains all the sentences in all other languages
• You can arrange data so that no one ever learns Linfinity
– http://www.lps.uci.edu/~johnsonk/Publications/Johnson.GoldsTheorem.pdf