Transcript Lecture slides - Department of Computer Science and Engineering

An Introduction to
Semantic Parts of Speech
Rajat Kumar Mohanty
rkm[AT]cse[DOT]iitb[DOT]ac[DOT]in
Centre for Indian Language Technology
Department of Computer Science and Engineering
Indian Institute of Technology Bombay
Mumbai, India
Outline
 Conceptual Constituents
 Markedness Convention
 Place- and Path-function
 Conceptual Constituents of Motion Verbs
 Mapping a Thing into a Path
 Multiple Subcategorization
 The Case of climb
 Multiple Expressions of Path
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Conceptual Constituents
 The semantic structure of a sentence is built up from
a hierarchical arrangement of conceptual
constituents.
 Each of the conceptual constituents belongs to a
major ontological category or semantic part of
speech.
 Semantic POS: Thing, Place, Path, Event, State,
Manner, and Property
 Conceptual constituents are realized syntactically by
means of major phrasal constituents (such as, NP, S,
PP, AP, AdvP)
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Example
 Bill ran into the room
 Syntactic Structure:
[S [NP Bill] [VP ran [PP into [NP the room]]] ]
 Conceptual Structure:
GO ([Thing Bill ], [Path TO [Place IN [Thing the room] ] ])
Event
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Markedness Convention
 The correspondence of semantic to syntactic
categories is governed by markedness convention.
 The unmarked realization of





Thing is NP
Place and Path is PP
Property is AP
Manner is AdvP
Event and State is S
 However, the marked realizations also occur.
 The NP a bummer expresses Property
 The NP earthquake expresses an Event
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Place- and Path-function
PLACE
PLACE-FUNCTION ( [THING] )
Place
(e.g., in the room)
PATH
Path
TO
FROM
TOWARD
VIA
(e.g., to the station)
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( [THING] )
Motion Verbs
 Motion verbs map two arguments, a Thing and a
Path, into an Event consisting of the Thing traversing
the Path. (e.g., John ran into the room)
 Lexical entry:
run
+V, -N
[ _ PPj ]
[Event GO ([Thing i ], [Path
j ] ] ])
 Motion verbs are represented generically by GO and
differentiated from one another by various markers of
manner.
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Mapping a Thing into a Path
 The preposition into is a function that maps a thing –
the reference object – into a Path.
 Lexical entry:
into
P
[ _ NPj ]
[Path TO [Place IN [Thing
j ]]]
 To satisfy the well-formedness conditions on the use
of into, its sister phrase must be an NP (the syntactic
condition) and must express a concept of a category
Thing (the semantic condition).
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Example
 John entered the room
 Lexical
entry:
enter
+V, -N
[ _ NPj ]
[Event GO ([Thing i ], [PathTO [PlaceIN [Thing
 The position and category of the variable in enter
result in a syntactic realization as transitive verbs
plus NP instead of verb plus PP.
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j ]]])
Multiple Subcategorization
 The verb climb occurs in three subcategorization
frames:



[ __ ]
(e.g., She climbed)
[ __ NP] (e.g., She climbed the stairs)
[ __ PP] (e.g., She climbed through the window)
 Motion is carried out in a clambering fashion (the
precise nature of the manner depends on the character of the
direct object)
 The motion is understood as



Upward
Upward to the top (roughly) to the object NP
Not necessarily upward (the PP frame is more distantly
related)
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The case of Climb
 Lexical
entry:
climb
+V, -N
a. [ _ NPj ]
GO [Thing i ],
Event
UPWARD
[Path TO TOP OF
VIA
[Manner CLAMBERING ]
b. [ _ PPj ]
GO [Thing i ], [Path
Event
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j
]
[Manner CLAMBERING ]
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[Thing
j
]]
The case of Climb
 The subentries differ in how the Path is specified.
 The subentry (a) combines the transitive and




intransitive subcategorization frames.
The subentry (b) contains the PP frame.
Something is climbing is an Event.
The Event is constituted of motion (the semantic
function GO) of a Theme (the argument i ) along a
Path (the argument j ).
The semantic structure of climb has two argument
positions


a Thing-variable embedded in the Path TO TOP OF j
and
a Path-variable that itself fills the Path argument of GO
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Multiple Expressions of Path
 Examples


John climbed the mountain up a narrow path
John ran through the field into the woods.
(Two PPs expresse part of the same Path)
 The PPs (up a narrow path and into the
woods) are non-subcategorized PPs in V`,
which are interpreted as extra constituents of
the Path in Semantic Structure.
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Sources & further Readings
 Jackendoff, R. 1985. Multiple
Subcategorization and The θ-criterion: The
case of climb. Natural Language and
Linguistic Theory 3.
 Jackendoff, R. 1990. Semantic Structures.
The MIT Press, Cambridge, Mass.
 Jackendoff, R. 1997. Semantics and
Cognition. The MIT Press, Cambridge, Mass.
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Thank You
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