Linguistics 187/287 Week 2

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Linguistics 187/287 Week 2
Engineering and Linguistic Generalizations

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• Homework
• Due Friday
• Can discuss in class or via email or ask us for
  office hours
• Last assignment
• How much time?
• Trouble access, procedure?
• Issues XLE, LFG, grammar?

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Topics for this week

• Notation in LFG (more background)
• Templates
• Lexical rules
• Configurations
• Feature declaration
• Metarulemacro

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Grammar engineering for deep processing

• Draws on theoretical linguistics, software
  engineering
• Theoretical linguistics gt papers
• Generalizations, universality, idealization
  (competence)
• Software engineering gt programs
• Coverage, interface, QA, maintainability,
  efficiency, practicality
• Grammar engineering
• GrammarTheory ProgramProgramming language
• Reflect linguistic generalizations
• Respect special cases of ordinary language
• Deal with large-scale interactions
• Theory/practice trade-offs

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Grammar Engineering and Linguistic Theory

• Description vs. representation
• Program vs. data
• Expressiveness of notation
• Regular predicates for c-structure
• Boolean combinations (esp. disjunction)
• Equality, set-membership
• Defaults and marking conventions
• Constraining vs. defining, existentials, defaults
• Abbreviation and factoring
• Templates, macros, lexical rules
• Configuration management
• Combining rules, templates, lexicons
• Priority of core/specializations/extensions

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Description vs. Representation

• Complexity trades (program vs. data)
• Simplify descriptions but complicate
  representations
• Complicate descriptions but simplify
  representations
• Example Arguments and adjuncts
• Different behavior
• Arguments selected by predicate, unique
• Adjuncts modify predicate, multiple instances
• Similar behavior Can both be questioned
• Representation solution (HPSG)
• ARG ADJ DEP ARG ? ADJ
  (new type)
• Description solution (LFG)
• ARG ADJ ARG ADJ

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Description vs. Representation

• External constraints on representation
• Linguistic theory
• Applications
• Multilingual/cross-grammar similarity

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Expressiveness of notation

• Regular predicates for c-structure

Simple context-free rules
Compact notation
NP --gt N NP --gt Det N
NP --gt (Det) N optionality
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Expressiveness of notation and Representation

• Equality attribute values
• Set-membership sets and elements
• Adjuncts PP ( ADJUNCT)!
• PP ! ( ADJUNCT)
• Coordination (more next week)
• NP --gt NP ! CONJ NP ! .
• Semantic forms
• ( PRED)kicklt( SUBJ)( OBJ)gt
• Semantic relations, instantiation,
  subcategorization

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Defaults and Marking Conventions

• Constraining vs. defining
• Must be assigned nom ( SUBJ CASE)c nom
• Is nom ( SUBJ CASE)nom
• Existentials
• Must have case ( CASE)
• Defaults
• NTYPE proper pronoun common
• ( NTYPE) ( NTYPE)common
• ( NTYPE)common
• 
  (make choices disjoint)

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Abbreviations and Factoring

• Templates
• Capture generalizations of annotations
• Maintainability changes, mistakes
• Compare HPSG type hierarchy
• Macros
• Capture generalizations of rules
• Lexical Rules
• Theoretical proposal to manipulate predicates
• Implemented to expand lexicons consistently

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Example The verb bakes

• Belongs to several classes
• Third-person, singular, present-tense verb
• Transitive or intransitive
• Shares
• Some properties with falls
• Other properties with cooked

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The lexicon à la Kiparsky

• A dumping ground for exceptions
• A kind of appendix to the grammar, whose
  function is to list what is unpredictable and
  irregular about the words of a language

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The lexicon à la Bresnan

• A repository of linguistic generalizations
• Active and passive forms are related by lexical
  rules, not syntactic transformations
• ( SUBJ) ? ( OBL-AG)
• ( OBJ) ? ( SUBJ)
• Rules relating lexical items are a prime locus of
  syntactic generalizations

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The lexicon à la Flickinger

• A hierarchical structure of classes
• Each class represents some piece of syntactic
  information
• bakes belongs to
• the third-person singular present-tense class
• (like appears)
• the transitive/intransitive class
• (like cooked)
• and others
• Classes may be subclasses of other classes
• Classes may partition other classes along several
  dimensions

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LFG Relations between descriptions
LFG can encode linguistic generalizations
asrelations between descriptions of structures

• LFG functional description is a collection of
  equations
• These can be named
• This name can stand for those equations in
  linguistic descriptions
• Named descriptions are referred to as templates
• Interpretation Simple substitution
  Template-description is substituted for
  template-name that appears in (is invoked by)
  another description

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3SG and PRESENT templates

• 3SG ( SUBJ PERSON) 3
• ( SUBJ NUM) SG.
• 3SG names ( SUBJ PERSON)3 ( SUBJ
  NUM)SG
• PRESENT ( TENSE) PRES.

_at_ marks invocation (in lexicon, rules,
templates) Substitute ( TENSE)PRES for
_at_PRESENT in other descriptions
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Templates enable hierarchical generalizations

• Template definitions can refer to other templates
  by name
• E.g. further divide 3SG into
• 3PERS ( SUBJ PERSON) 3.
• SING ( SUBJ NUM) SG.
• then 3SG _at_3PERS _at_SING.
• Hierarchy of references represents inclusion
  hierarchy of named descriptions
• Frequently repeated subdescriptions
• specified in one place
• effective in many

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Hierarchy of template invocations

• Sharing in verb agreement

SING
3PERS
PRESENT
3SG
PRES3SG

• Boolean combinations of template references
• (just like ordinary descriptions)
• Sharing is distinct from mode of combination

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Functional description for bakes

• ( PRED)bakeltSUBJ,OBJgt (
  PRED)bakeltSUBJgt
• ( TENSE)PRES
• ( SUBJ PERS)3
• ( SUBJ NUM)SG
• With agreement template
• ( PRED)bakeltSUBJ,OBJgt (
  PRED)bakeltSUBJgt
• _at_PRES3SG
• Agreement template invoked by other verbs

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Templates with parameters Valency
Pargram convention Parameters begin with _

• TRANS-OR-INTRANS(_p)
• ( PRED) _pltSUBJ, OBJgt
• ( PRED) _pltSUBJgt .
• PRED value as a parameter of the template
• _at_TRANS-OR-INTRANS(bake)
• ? ( PRED) bakeltSUBJ, OBJgt
• ( PRED)
  bakeltSUBJgt
• Arguments can substitute for any part of an
  f-description
• Attributes
• Values
• Semantic relation-names
• Descriptions

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Valency hierarchy

• TRANS-OR-INTRANS(p)
• _at_INTRANSITIVE(p) _at_TRANSITIVE(p)
  .
• INTRANSITIVE(p) ( PRED)pltSUBJgt
• TRANSITIVE(p) ( PRED)pltSUBJ, OBJgt.

INTRANSITIVE
TRANSITIVE
TRANS-OR-INTRANS
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Templates and generalizations bakes

• bakes _at_TRANS-OR-INTRANS(bake) _at_PRES3SG
• TRANS-OR-INTRANS(p) shared by eat, cooked,
• PRES3SG shared by appears, goes, cooks,
• PRESENT
• used by PRES3SG template
• shared by bake, laugh, etc.

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Lexical sharing
3PERS
SING
INTRANSITIVE
TRANSITIVE
PRESENT
3SG
TRANS-OR-INTRANS
PRES3SG
bakes
cooked
falls
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Type hierarchy vs. templates

• Templates can play the same role as hierarchical
  type systems in theories like HPSG
• A notational device for factoring descriptions
• Interpreted as simple substitution
• Not part of a formal ontology
• Do not require an elaborate mathematical
  characterization

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Templates also invoked by Rules

• Rule annotations can also call templates
• Global changes, typo prevention
• Example adjunct annotation
• PP ! ( ADJUNCT) (! ADJ-TYPE)VP
• ADVP ! ( ADJUNCT) (! ADJ-TYPE)VP
• ADJ(_T) ! ( ADJUNCT) (! ADJ-TYPE)_T.
• PP _at_(ADJ VP) PP _at_(ADJ NP)
• ADVP _at_(ADJ VP) ADVP _at_(ADJ S)

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Templates Rules

• Example null pronouns
• Push it! They left (in order) to be on time.
• NULL-PRON(_P) (_P PRED)pro
• (_P
  PRON-TYPE)null.
• VPimp --gt VP _at_(NULL-PRON ( SUBJ)).
• VPimp --gt VP ( SUBJ PRED)pro
• ( SUBJ PRON-TYPE)null.

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Templates Extend notation

• DEFAULT(D V) D DV DV .
• e.g. _at_(DEFAULT ( NTYPE) common)
• IF(P1 P2) P1 P2
• IFF(P1 P2) P1 P2 P1 P2 .

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Templates and Principles

• Subject principle every verb has a subject.
• Implementaton
• VERB ( SUBJ).
• Put _at_VERB in every verbal entry.
• or
• Put _at_VERB in the templates called by the verbal
  entries.

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Lexical Rules

• Theoretical construct
• Templates can often achieve the same result
• Disjunction of several templates
• Parameterization of a complex template

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Lexical Rules Example

• Active
• They ate the cake.
• ( PRED)eatlt(SUBJ)(OBJ)gt'
• Passive
• The cake was eaten.
• ( PRED)'eatltNULL (SUBJ)gt'
• Could have VTRANS have two disjuncts
• Or manipulate PRED with lexical rule

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Lexical Rules Example

• Passive lexical rule
• _SCHEMA is a subcategorization frame
• PASSIVE(_SCHEMA)
• _SCHEMA ( PASSIVE)-
• _SCHEMA
• ( SUBJ) --gt NULL
• ( OBJ) --gt ( SUBJ)
• ( PASSIVE)c .
• Example calls
• TRANS(_P) _at_(PASSIVE ( PRED)'_Plt(SUBJ)(OBJ)gt'
  ).
• DITRANS(_P) _at_(PASSIVE ( PRED)'_Plt(SUBJ)(OB
  J)(OBJ2)gt').

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Lexical Rules Summary

• Lexical rules manipulate arguments of predicates
• capture systematic alternations like
  active-passive
• Rename and remove roles
• No good implementation for adding roles
• causative
• complex predicates
• benefactives

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Configuration Management

• Combining rules, templates, lexicons,
• System needs to know where everything is
• For large grammars, need modularization (multiple
  grammar rule files, multiple lexicons)
• Priority of core/specializations/extentions
• Want to specialize a grammar
• No questions in instruction manuals
• Loosen subj-V agreement
• Have lexicons of varying quality

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Combining Rules, Templates, Lexicons

• XLE configuration section
• Specify what files are called
• Specify which rule, template, and lexicon
  sections are used
• RULES (TOY ENGLISH).
• RULES (CORE ENGLISH) (SPECIAL ENGLISH).
• Other grammar information

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Configurations and Declarations

• Configurations
• File management
• Priority
• Declarations
• Governable relations and semantics
• Features
• Global Operators
• METARULEMACRO

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Files

• Priority ordered rules/entries in later files
  override those in earlier ones
• Example
• FILES standard-english-rules.lfg
• eureka-english-rules.lfg
• standard-english-lexicon.lfg
• eureka-english-lexicon.lfg.

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Eureka vs. Standard rules

• STANDARD ENGLISH RULES (1.0)
• N --gt _at_NOUN-COMMON
• _at_NOUN-PROPER.
• NOUN-COMMON -gt
• NOUN-PROPER -gt
• EUREKA ENGLISH RULES (1.0)
• N --gt _at_NOUN-COMMON
• _at_NOUN-PROPER
• _at_NOUN-EUREKA
• N PL .
• NOUN-EUREKA --gt EUR-PART EUR-NUM .

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Sections Used

• All lexicon, rule, and template sections have
  names and versions.
• These are called in priority order in the config.
• Use with the file order to create overrides.
• RULES (STANDARD RULES) (EUREKA RULES).
• LEXENTRIES (all all).

Versions allow for future XLE upgrades
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Multiple Lexicon Sections

• LEXENTRIES (AUTOMATIC ENGLISH)
  
• 
  (CORRECTED ENGLISH).
• AUTOMATIC ENGLISH LEXICON (1.0)
• appear V XLE _at_(V-TRANS appear)
• _at_(V-INTRANS
  appear).
• CORRECTED ENGLISH LEXICON (1.0)
• appear V XLE _at_(V-INTRANS appear)
• _at_(V-SUBJ-XCOMP
  appear).

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Other Configuration Information

• ROOTCAT default top level category
• Standard ROOT, Eureka FIELD
• Nondistributives for coordination
• External attributes for applications
• Character encoding
• Reparse category and Optimality order for
  robustness
• See XLE documentation for complete list

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Declarations

• Must declare grammatical and semantic functions
  for each grammar.
• Used for completeness and coherence
• GOVERNABLERELATIONS
• Functions (features) that must be subcategorized
  for in the PRED
• SUBJ OBJ OBL-? ?COMP etc.
• SEMANTICFUNCTIONS
• Functions that must have a PRED
• ADJUNCT NMOD

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Feature Declaration

• List of all the features
• GGF and semantic functions need not be listed
• all other features must be listed
• List of their possible values
• atomic
• f-structure
• Multiple feature declarations
• multilingual setting
• grammar specialization

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Why a feature declaration?

• Good engineering practice
• Catch typos and old analyses
• Grammar easier to read
• NB Theory doesnt have typos

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Declaration format

• STANDARD LANGUAGE FEATURES (1.0)
• feature1 -gt val1 val2 val3 .
• feature2 -gt val4 val 5 .
• feature3 -gt ltlt feature1 feature2 .
• feature4.
• ----

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Sample feature declaration

• TOY ENGLISH FEATURES (1.0)
• NUM -gt sg pl .
• PERS -gt 1 2 3 .
• TNS-ASP -gt ltlt TENSE MOOD ASPECT .
• TENSE.
• MOOD -gt indicative subjunctive .
• ASPECT -gt ltlt PERF PROG .
• PERF -gt - .
• PROG -gt - .

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XLE and the feature declaration

• XLE will not load a grammar with a violation of
  the feature declaration.
• To catch violations in the lexicon, the generator
  must be loaded.
• regenerate some-sentence-to-parse
• parse, then choose generate in f-str window
• create-generator grammar-name.lfg
• print-unused-feature-declarations

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Multiple feature declarations

• List in priority order in the configuration
• FEATURES (STANDARD COMMON)
• 
  (STANDARD ENGLISH).
• New features are listed as usual
• Changes to features use edit operators
• add a new value
• intersect the values
• ! replace the feature entirely

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Multiple feature declarations

• STANDARD COMMON FEATURES (1.0)
• NUM -gt sg pl dual .
• CASE -gt nom acc .
• TENSE -gt ltlt PAST FUTURE .
• PAST -gt - .
• FUTURE -gt - .
• STANDARD ENGLISH FEATURES (1.0)
• PERS -gt 1 2 3 .
  PERS -gt 1 2 3 .
• NUM -gt sg pl . NUM
  -gt sg pl .
• CASE -gt gen . CASE
  -gt nom acc gen .
• !TENSE -gt pres past fut . TENSE -gt
  pres past fut .
• !PAST -gt .
• !FUTURE -gt .

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Using Multiple Feature Decl.

• Multilingual contexts
• Language universal features
• Customize to particular language
• Grammar specialization
• Add new features for odd constructions
• Remove unused choices

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Global Operations METARULEMACRO

• System defined function
• Operates on every category
• Global statements
• Linguistic subject condition
• SUBJ lt OBJ
• coordination
• Engineering quotes
• bracketing

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METARULEMACRO

• Right-hand side of each grammar rule is the
  result of applying the macro to the rule
• METARULEMACRO(_CAT _BASECAT _RHS)
• _RHS.

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Punctuation and METARULEMACRO

• Surround any constituent with quotes
• METARULEMACRO( _CAT _BASECAT _RHS)
• _RHS
• L-QT
• _CAT
• R-QT
• L-DQT
• _CAT
• R-DQT.

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Punctuation cont.

• Mary and John left them there.
• We saw them in the garden.
• They appeared and then disappeared.'

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Punctuation Problem

• Vacuous branching results in many analyses

NP
etc.
Nzero
N
bagels
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Solution PUSHUP

• If non-branching, push up to highest node.
• METARULEMACRO(_CAT _BASECAT _RHS)
• _RHS
• L-QT
• _CAT _at_PUSHUP
• R-QT .
• How to define PUSHUP?
• Need to test existence of sister nodes MOTHER
  SISTER

PUSHUP ( MOTHER LEFT_SISTER)
( MOTHER RIGHT_SISTER)
( MOTHER LEFT_SISTER)
( MOTHER MOTHER) .
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Summary

• Lexical rules allow for generalizations over
  predicate alternations
• Configurations and declarations allow management
  of large-scale grammars
• readability and consistency
• maintenance
• specialization
• Global operators allow for cross-grammar
  generalizations
• coordination

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The HPSG lexicon a type hierarchy

• More specific types inherit information from less
  specific
• Types and subtypes
• A mathematical relation between structures
  AND/OR lattice
• Different subtypes represent alternatives/disjunct
  ion
• Multiple supertypes represent conjunction

head
(Malouf)
OR
noun
relational
AND
c-noun
gerund
verb

• LFG does not use typed feature structures for
  lexical generalizations

but type inheritance is not the only (best?)
way to express generalizations
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Coordination without METARULEMACRO

• Want to coordinate any constituent
• Coordination macro
• SCCOORD(_CAT)
• _CAT !
• COMMA
• _CAT !
• CONJ
• _CAT ! .
• Put call in each rule
• NP (DET) AP N PP
• _at_(SCCOORD NP).
• Engineering problem
• forget to call
• put in wrong category

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Coordination with METARULEMACRO

• Call SCCOORD as part of MRM
• METARULEMACRO(_CAT _BASECAT _RHS)
• _RHS
• _at_(SCCOORD _CAT).
• NP rule now
• NP (DET) AP N PP.
• Effectively
• NP (DET) AP N PP
• _at_(SCCOORD NP.