Grammar is the study of the classes of words, their inflections (see inflection sense 2), and their functions and relations in the sentence. b : a study of what is to be preferred and what avoided in inflection (see inflection sense 2) and syntax (see syntax sense 1)
Inquiry on the Philosophy of Language.pptxutcrash88
It is a reasoned inquiry into the origins of language
Its nature of meaning
The usage and cognition of language
The relationship between language and reality
To clarify concepts with which language is described and analysed
To settle and resolve philosophical disputes originating from linguistic confusion
English dictionaries since 1755 have attempted to present succinct statements of the meaning(s) of each word. A word may have more than one meaning but, so the theory goes, each meaning can in principle be summarized in a neat paraphrase that is substitutable (in context) for the target word (the definiendum). Such paraphrases must be so worded that the the substitution can be made without changing the truth of what is said – salva veritate, in Leibniz’s famous phrase. Building on Leibniz, philosophers of language such as Anna Wierzbicka have argued that the duty of the lexicographer is to “seek the invariant”.
In this presentation, I argue that this view of word meaning and definition may be all very well as a principle for developing stipulative definitions of terminology in scientific discourse, but it has led to serious misunderstandings about the nature of meaning in natural language, creating insuperable obstacles for the understanding of how word meaning works. As a result, linguists from Bloomfield to Chomsky and philosophers of language from Leibniz to Russell – great thinkers all – have been unable to say anything true or useful about meaning in language.
I argue that, instead, lexicographers should aim to discover patterns of word use in large corpora, and associate meanings with patterns instead of (or as well as) words in isolation.
They should also distinguish normal uses of each word from exploitations of norms.
Inquiry on the Philosophy of Language.pptxutcrash88
It is a reasoned inquiry into the origins of language
Its nature of meaning
The usage and cognition of language
The relationship between language and reality
To clarify concepts with which language is described and analysed
To settle and resolve philosophical disputes originating from linguistic confusion
English dictionaries since 1755 have attempted to present succinct statements of the meaning(s) of each word. A word may have more than one meaning but, so the theory goes, each meaning can in principle be summarized in a neat paraphrase that is substitutable (in context) for the target word (the definiendum). Such paraphrases must be so worded that the the substitution can be made without changing the truth of what is said – salva veritate, in Leibniz’s famous phrase. Building on Leibniz, philosophers of language such as Anna Wierzbicka have argued that the duty of the lexicographer is to “seek the invariant”.
In this presentation, I argue that this view of word meaning and definition may be all very well as a principle for developing stipulative definitions of terminology in scientific discourse, but it has led to serious misunderstandings about the nature of meaning in natural language, creating insuperable obstacles for the understanding of how word meaning works. As a result, linguists from Bloomfield to Chomsky and philosophers of language from Leibniz to Russell – great thinkers all – have been unable to say anything true or useful about meaning in language.
I argue that, instead, lexicographers should aim to discover patterns of word use in large corpora, and associate meanings with patterns instead of (or as well as) words in isolation.
They should also distinguish normal uses of each word from exploitations of norms.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
2. What is a Grammar Formalism?
From Formal Language Theory
• A language
– A language L is a possibly infinite set of strings.
– The strings are made from a finite alphabet.
• The “alphabet” might be the words of English
• Henceforth, we will call it the “vocabulary”
– Some strings of language L:
• Bears live in the forest.
• Never have I seen such ridiculous beasts.
– Some strings are not in L:
• *Never I have seen such ridiculous beasts.
• *Live bears the in forest.
• (* means that the string is not a member of the set of strings
that comprise the language L.)
3. What is a Grammar Formalism?
From Formal Language Theory
• A Grammar:
– A set of production rules.
– In addition to the vocabulary, the production
rules can use other symbols
• N (noun)
• V (verb)
• NP (noun phrase)
• VP (verb phrase)
– One symbol is special:
• S (sentence)
4. What is a grammar formalism?
Production Rules
• S → NP VP
• NP → Det N
• VP → V NP
• DET → the
• DET → a
• N → boy
• N → girl
• V → saw
• V → sees
These production rules have a non-
terminal symbol (one that isn’t from the
vocabuary) on the left, then an arrow,
then some terminal (from the vocabulary)
and non-terminal symbols on the right.
This is one instance of a grammar
formalism.
We will see that other grammar
formalisms use other types of symbols
and production rules.
5. What is a grammar formalism?
Derivation
• The production rules are interpreted as
instructions:
– Parsing: when you find the string on the right hand
side, replace it with the string on the left hand side.
– Generation: when you find the symbol on the left
hand side, replace it with the string on the right hand
side.
– Different grammar formalisms will have different
instructions.
• Your job:
– Generation: get from the special symbol S to a
terminal string (only symbols from the vocabulary).
– Parsing: get from a terminal string to the special
symbol S
6. What is a grammar formalism?
Derivation
• A derivation is the ordered list of production rules that you
use to get from the special symbol to the terminal string or
vice versa.
• S
• NP VP
• Det N VP
• Det N V NP
• Det N V Det N
• The N V Det N
• The girl V Det N
• The girl sees Det N
• The girl sees a N
• The girl sees a boy
S → NP VP
NP → Det N
VP → V NP
DET → the
DET → a
N → boy
N → girl
V → saw
V → sees
7. Reference
• Hopcroft, Motwani, and Ullman,
Introduction to Automata Theory,
Languages, and Computation, second
edition, Addison-Wesley, 2001.
– Chapter 5.2
8. What does a grammar formalism
look like?
• Context Free Phrase Structure Grammar:
S → NP VP
• Lexical Functional Grammar:
S → NP VP
(↑ SUBJ)=↓ ↑=↓
• Tree Adjoining Grammar
• Categorial Grammar
X → X/Y Y
(an X consists of an X missing a Y and a Y.)
X
Y
9. What is a Grammar Formalism for?
• Distinguish strings that are in the language
from those that are not in the language.
– The girl sees a boy.
– *Girl the the.
• No derivation exists using the grammar rules.
• Identify a structure for the sentence.
10. Structure
• S
• NP VP
• Det N VP
• Det N V NP
• Det N V Det N
• The N V Det N
• The girl V Det N
• The girl sees Det N
• The girl sees a N
• The girl sees a boy
S
NP VP
DET N V NP
Det N
A girl sees a boy
11. This grammar makes wrong
structures
• S → NP VP N
• NP → Det
• VP → N V Det
• DET → the
• DET → a
• N → boy
• N → girl
• V → saw
• V → sees
S
NP VP N
Det N V Det
the girl sees a boy
12. History of Grammar Formalisms
• 500 B.C.
– Pānini’s grammar of Sanskrit, Astadhyayi, contains production
rules (!!!) for Sanskrit phonology, morphology, and grammar.
– This is a lasting work of genius, still studied today, and remarkably
similar to some modern linguistic theories.
• 7th to 8th centuries A.D.
– Classical Arabic Grammarians define Classical Arabic.
• 19th century Europe
– No production rules. They spend all their time on historical and
comparative linguistics – finding genetic relationships among
languages:
– The Grimm brothers collect fairy tales, but are actually working on
systematic sound correspondences between branches of Indo-
European:
• p-f: père – father; pied – foot; etc.
13.
14. History of Grammar Formalisms
Late 19th to Early 20th centuries
• Ferdinand de Saussure
– Ferdinand de Saussure starts out as a historical linguist,
and then comes back to the present.
• Distinguishes synchronic linguistics from diachronic linguistics
– Linguistics gets mental:
• Signifier and signified:
– The signifier is a word, like “tree”. The signified is not a tree, but a
concept of a tree.
• Langue (language) and Parole (speech)
– http://www.press.jhu.edu/books/hopkins_guide_to_literary_theory/ferdinan
d_de_saussure.html
“… he distinguishes between the particular occurrences of
language – its particular "speech-events," which he
designates as parole –and the proper object of linguistics,
the system (or "code") governing those events, which he
designates as langue.”
15. History of Grammar Formalisms
Late 19th to Early 20th centuries
• Ferdinand de Saussure (continued)
– Structuralism:
• Elements of language are like pieces on a chess
board. They only make sense when you consider
their role in relation to other pieces.
– De Saussure’s students write up his lectures
in Course de Linguistique Générale.
– Structuralism becomes big in linguistics,
literary theory, art, anthropology, etc.
16. History of Grammar Formalisms
• Early 20th Century
– Linguistics gets scientific
• Structuralists focus on discovery procedures for phonemes
and morphemes.
• Structuralism is empiricist:
– Focus is on what is attested in the data
– The source of knowledge is sensory experience
• Some linguists use formal notation.
• But structuralism does not focus on a set of production rules
that define which strings are members of a language and
which are not.
– No derivations?
17. References
• R. H. Robbins, A Short History of
Linguistics, Indiana University Press,
1967.
• Frederick Newmeyer, Lingiustic Theory in
America, Academic Press, 1982.
19. History of Grammar Formalisms
• Mid to Late 20th century: Generative Grammar
• Before Chomsky:
– Post
– Bar Hillel
– Adjukiewicz
– Zellig Harris (Chomsky’s professor)
• “Kernel” sentences become the model for Chomsky’s deep
structures. Derived sentences are the model for surface structures.
– The police arrested the thief. (Kernel)
– The thief was arrested by the police.
– It was the thief who was arrested by the police.
– Shannon and Weaver: information theory
• Structuralists pay some attention to this, but then it falls out of
fashion for human language until about 1980.
• Becomes the basis for statistical NLP.
20. History of Grammar Formalisms
• 1950’s: Chomsky’s book The Logical Structure
of Linguistic Theory is not published.
– It was published in 1975
• 1957: Chomsky’s Syntactic Structures is
published.
– Generative Grammar is rationalist:
• The source of knowledge is reason, not experience.
– http://www.whps.org/schools/norfeldt/libraryweb/MediaResourc
es/TermPaper.PDF
• Grammaticality judgments are legitimate data.
• Generalization beyond what is in a corpus.
• Language is an infinite set of sentences defined by a finite
set of rules.
21. History of Grammar Formalisms
• Syntactic Structures (continued)
– Human language cannot be described
adequately by finite state machines.
• If….either…or… then…
• If either it’s raining or it’s snowing, then we won’t
go outside.
– You could get a given finite number of these right, but
your internal grammar tells you that the embedding is
potentially infinite.
• *If …either….either…then… or….
22. History of Grammar Formalisms
• Syntactic Structures (continued)
– Human language cannot be described well by
context free grammars
• Agreement
– S → NP-sg VP-sg
– S → NP-pl VP pl
– The girl sings.
– The girls sing.
– *The girl sing.
– *The girls sings.
23. History of Grammar Formalisms
• Syntactic Structures (continued)
– Add transformations – tree-to-tree mappings – to
generative grammars.
– Structuralism:
• Order of English auxiliary verbs:
• Modal have be (prog) be (pass)
• Modal must be followed by infinitive
• Have must be followed by past participle
• Be (prog) must be followed by present participle
• Be (pass) must be followed by a past participle in passive
voice.
24. History of Grammar Formalisms
• I will go.
• *I will gone/going/went.
• I have gone.
• *I have go/gone/going/went.
• I am going.
• *I am go/went.
– I am gone (adjective).
• I will have been being arrested.
• I will have been singing.
• *I will be having sung. (wrong order)
• *I will be sung. (wrong verb form.)
• Etc.
25. Affix Hopping
• Base rule:
– AUX → modal (have –en) (be –ing)
– Parentheses mean optionality
– Deep Structure
S
NP AUX VP
I will have en be ing go
26. History of Grammar Formalisms
• Surface structure
S
NP AUX VP
I will have be en go ing
There was a special
formalism for
transformations.
27. History of Grammar Formalisms
• Robert Lees writes an influential positive
review of Syntactic Structures.
• Many structuralists are impressed by the
insightful treatment of English auxiliary
verbs (affix hopping).
• Chomsky debates Piaget.
• Chomsky criticizes Skinner.
• Chomsky becomes one of the leading
intellectuals of the 20th century.
– Some people say the leading intellectual
28. Anecdotes
• Debating style of philosophers: How to
prove a point P:
– Davidson: As I have said before, P.
– Chomsky: P. Because what else? Q?
• Human language capabilities must be innate
because, what else? Something that complicated
could be learned so well by babies in such a short
time with corrupt input?
• Chomsky’s followers get a reputation for
being arrogant and obnoxious.
29. History of Grammar Formalisms
Transformation Grammar in the 1960’s and 1970’s
• Chomsky’s theories move from a set of rules to
a set of principles which predict which rules are
possible and which are not.
– X-bar theory: Chomsky (1970) “Remarks on
Nominalizations”; Jackendoff (1977) X-bar Theory.
• NP → V PP (not likely)
• NP → Det N (likely)
– John Robert (Haj) Ross (1967) Constraints on
transformations (not sure of the title); Chomsky
(1977) “On Wh Movement”
30. History of Grammar Formalisms
Transformation Grammar in the 1960’s and 1970’s
• Some of Chomsky’s followers spin off in different
directions:
– Generative Semantics
• All aspects of meaning are represented in deep structure.
• Speech acts are represented in deep structure. There has to be a
transformation to remove “I say to you” at the beginning of every
statement. (But “I promise you” usually does not get deleted.)
• There is some debate about whether the word “bachelor” has to be
derived from the deep structure “unmarried man.”
– Relational Grammar
• (Re-)introduced subject and object into generative grammar.
• Chomsky says that grammatical relations can’t be primitives of the
theory because the primitives have to be things that babies could
perceive like suffixes, word order, and agentivity/cause.
• Anecdote:
– People leave MIT. There are raging debates with the vehemence
of the times (late 60’s and early 70’s). Careers are ruined.
31. No more about Chomsky
• His systems of principles moved away
from formalization in a way that cannot be
easily implemented.
• But there are some principle based
parsers:
– See papers by these people: Weinberg,
Wehrli, Abney, Fong, Berwick
32. Montague Grammar
Syntax and Formal Semantics
• http://www-
unix.oit.umass.edu/~partee/docs/M
ontagueGrammarElsevier.PDF
• “Montague’s idea that a
natural language like English
could be formally described
using logicians’ techniques was
a radical one at the time. Most
logicians believed that natural
languages were not amenable
to precise formalization, while
most linguists doubted the
appropriateness of logicians’
approaches to the domain of
natural language semantics.”
• Precursor to Categorial
Grammar
Richard Montague
1930-1971
33. History of Grammar Formalisms
Some events in computational linguistics
• William Woods
(1970): “Transition
Network Grammars
for Natural Language
Analysis” in Grosz,
Sparck Jones, and
Webber (eds.)
Studies in Natural
Language
Processing, Morgan
Kaufmann, 1986. Bill Woods
Sun Microsystems
35. NP VP
Det Noun
Verb NP
PP
Augmented Transition Network
Recursive transition network with
actions for setting and checking
registers
Set Register
Subject
Set Register
Object
Set Register
Number
Check Number in
subject register
Subject: Number singular
Person 3
Root girl
Register Structure
36. History of Grammar Formalisms
Some events in computational linguistics
• Martin Kay, “Parsing
in Functional
Unification Grammar”,
in Grosz, Sparck
Jones, and Webber
(eds.)
– Not sure what year
Kay’s paper was
originally published
Martin Kay
PARC (?)
41. Lexical Functional Grammar
• Bresnan (linguist) wanted to create a
“realistic” transformational grammar.
– Grammatical relations (subject and object)
– No empty categories
– Passivization as a lexical rule rather than a
tree-to-tree mapping.
• Kaplan (computational psycholinguist) was
working at Xerox PARC with Martin Kay.
42. Local co-description of partial
structures
• S NP VP
( SUBJ) = =
NP says: My mother’s f-structure has a SUBJ
feature whose value is my f-structure.
VP says: My mother’s f-structure is my f-structure.
This rule simultaneously describes a piece of c-
structure and a piece of f-structure.
It is local because each equation refers only to the
current node and its mother. (page 119-120)
43. Levels of Representation
• Transformational Grammar
– Deep structure: represents meaning
• Sentences that mean the same thing have the same deep
structure
– Surface structure: represents word order and
represents grammatical relations indirectly
• Lexical Functional Grammar
– Constituent structure: represents word order and
groupings of words into phrases.
– Functional structure: represents grammatical relations
explicitly.
– Argument structure: represents meaning
44. Unification Based Formalisms
• Shieber and Pereira
– Prolog and Natural
Language Analysis,
CSLI, 1987.
• Prolog has built in
unification and
backtracking.
– PATR formalism
S NP VP
(X0 SUBJ) = X1
X0 = X2
Fernando Pereira
University of Pennsylvania
Stuart Shieber
Harvard
45. The Tomita Parser
• Around 1985
• Based on PATR and LFG
• One of the first unification
based parsers that was
fast enough to use for
real applications.
• Tomita was co-founder of
the CMT, which later
became the LTI.
• Several of you are using
the Tomita parser or a
descendent of it in your
current research.
Masaru Tomita
Keio University
46. Generalized Phrase Structure Grammar (GPSG)
Precursor to HPSG
Ewan Klein
Edinburgh
Ivan Sag
Stanford
Geoffrey Pullum
UC Santa Cruz
Gerald Gazdar
Sussex
48. The nature of syntactic categories: GPSG and HPSG
• Generalized Phrase Structure Grammar (GPSG,
Gazdar, Pullum, Sag, and Klein):
– Claimed that human language syntax could be handled with
context free rules.
• Categories in GPSG:
– Handling dependencies like subject-verb agreement using
context free rules (hypothetical language)
• S NP-sg-fem VP-sg-fem
• S NP-pl-fem VP-sg-fem
• S NP-[num x, gen y] VP-[num x, gen y]
• Node labels like NP and VP turned into feature structures.
– Immediate dominance and linear precedence
• Context phrase structure rules specify dominance and precedence
• For languages with free word order, it makes sense to separate
dominance from precedence.
– S dominates a V, some NPs, and some PPs
• Generalizations about precedence can hold over all the rules.
– Japanese is head-final: V is final in S. N is final in NP. P is final in
PP.
49. GPSG and HPSG
• Since context free rules aren’t very pretty,
GPSG introduced meta-rules and rule
schemata to make the grammar more elegant.
• Then it was discovered that some of the meta
rules weren’t context free (Shieber 1985).
50. Head Driven Phrase Structure Grammar
• By that time, Carl Pollard had started
working on HPSG using some ideas
that followed naturally from GPSG:
– Node labels were feature structures
instead of atomic categories like NP
and VP
– Generalizing from GPSG rule
schemata lead to the special
treatment of phrasal heads
– Unification was becoming popular
with LFG and PATR.
• Pollard added:
– Typed feature structures
– HPSG is a system of principles that
predict which rules occur.
• Carl Pollard did some of this work at
CMU in the old Computational
Linguistics Program in the
Philosophy Department.
Carl Pollard
Ohio State Univ.
Ivan Sag
Stanford
51. HPSG: Things not handled well by context
free grammars
• Headedness
– Some rules are more likely than others
• NP → V PP (not likely)
• NP → Det N (likely)
– The head determines the properties of the phrase.
• The smart students in the class studied hard.
• Girls determines that the noun phrase is plural.
• Studied determines that the sentence is past tense.
• Subcategorization
– Subcategories of verbs that occur in different contexts:
• No direct object: Some problems exist.
• One direct object: The children ate.
• Direct and indirect objects: The teacher handed books to the
students.
• Etc.
52. HPSG Principles/Rule Schemata
phrase
COMPS < >
word
H COMPS < [1]….[n]>
[1] … [n]
Summarizes many rules:
VP → V-intrans
VP → V-trans NP
AP → Adj VP (happy to be here)
NP → N PP (student of linguistics)
Head Complement Rule
53. Categorial Grammar
• History
– appears around 1980
– Fits well with Montague
Grammar
• Key features
– Compositionality
• The meaning of a phrase is a
function of the meanings of its
parts.
– put more information in lexical
items rather than rules
• E.g., “devour” has to occur with
an NP to the left and an NP to
the right.
– Does "non-constituent
coordination" well.
• John wrote and Bill signed the
letter.
• I gave a book to Mary and a
CD to Sue.
Mark Steedman
Edinburgh
54. Categorial Grammar Example
Example Rules
Forward application : X/Y Y => X
Backward application: Y XY -> X
Lexical items
John np
Mary np
loves (snp)/np
Derivations
John likes Mary
np (snp)/np) np
---------- Forward
snp
---------- Backward
s
55. Tree Adjoining Grammar
• Describe a language of trees
rather than strings (which trees
are licensed by the grammar)
• Easier to encode linguistically
well-motivated grammars and
constraints:
– Separation of recursion from
linguistic constraints and
dependencies (constraints can
be specified within the scope
of individual elementary trees)
– Each elementary tree can be
lexicalized
• Can describe “mildly-context-
sensitive” languages.
Aravind Joshi
University of Pennsylvania
57. Summary
• Grammar formalisms consist of production rules
– The production rules are declarative – a description, not an procedure.
– The production rules specify which strings are in the language and which aren’t.
– The production rules specify a structure.
– There may be more than one kind of structure (Levels of representation), for
example a phrase structure tree, a feature structure, and a logical formula.
• Feature structures and unification play a big role in most modern formalisms.
• Lexical Functional Grammar focuses on the role of grammatical relations in
universal grammar, and how they are encoded in phrase structure.
– Rules take the form of co-descriptions of pieces of constituent structures and
feature structures.
• HPSG focuses on the nature of syntactic categories – typed feature
structures.
– Rules take the form of schemata that are actually summaries of many rules.
• Tree Adjoining Grammars consist of elementary trees that can be combined.
• Categorial grammars focus on compositionality of syntax and semantics.
• Lexicalization is an important concept.
– Many grammar rules can be stated as requirements of lexical items.
58. Grammar formalisms and other topics not covered
in this class
(Can be used for term projects)
• Link grammar (Sleator and Lafferty)
• Dependency Grammar
• Construction Grammar
• Formalisms for morphology
• Treebanks (English, Chinese, Czech)
• Generative capacity
• Applications – machine translation, IR, etc.
• Chomsky’s current theories