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Ch-3: Linguistics Essentials
Prepared by Qaiser Abbas (07-0906)
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3.1 POS and Morphology
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Important POS are noun, verb and adjectives.
Basic test for word belonging to the same
category is substitution test e.g. adjectives in fig
3.1
Many words have multiple POS e.g. candy can
also be a verb as in (Too much boiling will candy
the molasses).
Word Classes: divided in two. 1. open or lexical
which have large number of members e.g. noun,
verb and adjectives. To which new words are
commonly added 2. Closed or functional such as
preposition and determiners containing words like
of, on, the, a which have only a few members and
clear grammatical use.
POS tags: (already known in CL)
Morphological Processes like singular to plural
already known in CL. However in English regular
verb has 4 distinct forms and irregular verb have
at most 8 forms. In Finish verb has more than
10,000 forms.
Morphology include concept of inflection
(modification of root form through suffix, prefix etc.
as shown in table 1.3), derivation (radical change
of syntactic category and often change in meaning
e.g. adverb widely from adjective wide) and
Compounding (merging two words into a new
word e.g. tea kettle, college degree, etc).
•Antecedent:
comes
Noun, Pronounaorword
Adjective
whenbefore
1. Subject
a verb (nominative)
another
andofinfluence
it e.g. “He
2. It is used to show possession or close
grabbled the ball and threw it in the
connection b/t two things (Genitive)
air”3. here
ball is object
antecedent
It is indirect
of a verb of
or it.
connected with the indirect
•The other
detail e.g.
is shown
object(dative)
I sent herina table
3.2. it postcard
is pertinent
to note
that
(word her
is dative)
4. It is in
the directare
object
or connected
reflexive
pronoun
also
known
with the direct object (accusative) e.g.
as anaphors
e.g. each other
I saw him today (him is direct object)
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3.1.2: Words that accompany nouns: Determiners and Adjectives
• Determiner describe the particular reference of a noun. A subtype is
article which indicates that we are talking about something or
someone that we already know about or can uniquely determine e.g.
the tree (standing in front of tree) and a tree ( not known about the
tree).
• Adjectives describe the properties of noun e.g. a red rose, this long
journey etc. Uses such as these modifying a noun are called
attributive or adnominal.
• Adjective also have predicative (use after verb) use e.g. “The rose is
red. The journey will be long”.
• Article and Adjectives agrees with the noun because many
languages mark distinction of case, number and gender on articles
and adjectives as well as nouns.
• Adjectives has positive (basic form), comparative, superlative,
periphrastic forms (more intelligent, most intelligent)
• Brown Tags: Adjective Positive form (JJ), Comparatives (JJR),
superlatives (JJT), Semantically superlative adjective (JJS) e.g.
chief, main and top, Numbers are subclasses of adjectives included
cardinals (CD), ordinals (OD), Articles (AT), singular determiners like
this, that have the tag DT, plural determiners (DTS) and others tags
can be seen in the text book p88.
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3.1.3: Verbs
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Verbs are used to describe actions (she threw the stone), activities (she walked
along the river) and states (I have $50). Have 4 morphological forms e.g. walk,
walks, walking, walked
Base form with infinitive ‘to’, progressive form is ‘ing’,
Irregular verbs like drive and take. Table 3.3 summarizes grammatical features
Words that accompany verbs in a verb group are called analytically or feature
indication with auxiliaries e.g. have , will and be to express aspect, mood and
some tense information.
Modal auxiliaries or modal is class of verbs with special properties. They express
modalities like possibility (may, can), or obligation (should) etc.
Base form of verb (VB), VBZ for 3SG(takes), VBD for past tense, VBG for gerund
and present participle (taking), VBN for past participle (taken). Tag for modals is
MD. See detail in table 4.6
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3.1.4: Other POS (Adverbs, Prepositions, Particles)
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Adverbs specify place, time, manner or degree. It modifies a verb in the same
way as adjective modifies noun e.g. “She often travels to Las Vagas” or “she
allegedly (fact without proof) committed perjury (crime of telling a lie in court of
law)”
Some adverbs can also modify adjectives (a very unlikely event) and other
adverbs (she started her career off very impressively) and do not modify verbs
known as degree adverbs. Some times known as qualifiers.
Preposition: express spatial relationship e.g. in the glass, on the table, over their
heads (already known in CL)
Particles: subclass of preposition that can enter into strong bond with verbs in
the formation of phrasal verbs e.g. The plane took off at Sam, Don’t give in to
him. Some time preposition separated from the verb e.g. He put me off. These
phrasal verbs have particular meaning and quite specialized and unpredictable
from the verb and particle that make them up.
We need to know the meaning of a sentence to differentiate particle and
preposition e.g. She ran up a hill (up is preposition due to running on a incline
plane) and She ran up a bill (up is a particle due to figurative meaning of building
up a large bill)
RB (ordinary adverb e.g. simply, well etc.), RBR (comparative adverb e.g. later,
better, less), RBT (superlative adverb e.g. latest, best, least) and detail can be
seen in the text book
Conjunction and Complementizers ( already known in CL) however cases of
subordinating conjunction like that or use of for which introduces arguments of
the verb are known as Complementizers.
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3.2 Phrase Structure
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Words are organized into phrases,
grouping of words that are clumped
as unit
Syntax is the study of regularities and
constraints of word order and phrase
structure.
Verb
isusually
the head
of verb phrase,
NP
is
argument
of
Positional and Paradigmatic
organizes
all(3.29)
theverb
verb,phrase
contains
relationship
is shown
inoptional
example
elements
the
sentence
thatare
and
(3.30) asof
in zero
fig. Noun
phrases
determiner,
or more
members
of one
paradigm which
depend
syntactically
on thecan
AP,
a
noun
head
and
then
be replaced for each other. Two words
except
most
syntactic
bearverb
a syntagmatic
relationship
if they
some
post modifiers
can
form a phrase
(syntagma)
like
theories
the verb
phrase does
sewed clothes. Collocations are also
not contain
the
subject noun
important
class of
syntagmatically
related words. phrase.
Overall phrase structure of English
sentence is suggested in upshot (3.31)
Complex adjective phrase are less
common e.g. He seemed a man who
was quite certain to succeed.
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3.2.1: Phrase Structure Grammars
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Word order allows us who did what to whom as in
“Mary gave peter a book” and “peter gave Mary a
book”
Many languages
like Latin dependency
or Russian or Urdu
•Long distance
(movement theory) such as whpermit different ways of ordering without a change
extraction.
which
3.46(b) is moved from an underlying
in meaning.
However,
Englishbook
is veryinmuch
restrictive
in wordafter
order the
movement
e.g.in
in general
position
verb as
3.46a to their surface position (the
form “ The children (subject) should (auxiliary
beginning
of theand
sentence
as ine.g.
3.46b.
verb) eat
spinach (object)”
in interrogative
“should (auxiliary verb) the children (subject) eat
spinach
(object)?”a. should peter buy a book?
(3.36)
To produce a sentence, we start with the start
symbol ‘S’ in example (3.39). Such grammars are
b. which
book
peter buy?
known as CFG’s. with
these rules
weshould
can derive
sentence as in (3.40) and (3.41)
•SNLP
failway
in to
non
local dependency
situation e.g. an n-gram
The more
intuitive
represent
phrase
structure
is as apredict
tree as shown
(3.42)
and in 3.45 is was, which is not true.
model
word inafter
wallet
(3.43).
These
are discussed
in ch-11
Another
way to issues
show constituency
is via (labeled)
bracketing e.g. for (3.43)[S[NP[AT the][NNS
children][VP[VBD
ate][NP[AT
cake]]]]
•Empty nodes
are the][NN
required
in situation like eat the cake, in which
Rewrite
rules is recursive
and this property
is
subject
is not present.
So NP0
or e in this case.
known as recursivity. In fig3.1the sequence of
PP’s is generated by multiple application of the
rewrite rule cycle “NP NP PP; PPIN NP” .
Recursivity also expand sentence e.g. VP
expanded to nine words as in fig 3.1
Dependency through subject verb agreement e.g.
“The women who found the wallet were given a
reward”. Here women is subject and form of to be
in plural.
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3.2.1: Dependency: Arguments and Adjuncts
• “Sue watched the man at the next table”. Here Sue and the man are
arguments of the verb and dependents of watching event. Similar is
the case of PP with the man.
• Levels of arguments of the verb: as arguments via semantic roles
contains agent, patient and instrument & goal describe other classes
of semantic relationship. At syntactic level verb contains NP as sub
and obj. Note: only pronoun change their forms in obj case.
• Some verbs take two objects (direct & indirect) as in “she gave him
the book”, him is indirect and the book is direct object.
• Verbs of sending and communication such as “She sent her mother
the book”. Such verbs allow an alternate expression as “She sent
the book to her mother”. Language with case marking express
patients in the accusative case and recipients in the dative case.
• Semantic role and grammatical role is changed through voice
alternation. The agent is sub and patient in obj in active is reversed
in passive sentences and agent is expressed by prepositional byphrase.
• In other languages like Urdu the passive involves alternation in case
marking or some morphology on the verb.
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Sub categorization
Different verbs differ in the number of entities (persons, animals, things) that
they relate e.g. “She brought a bottle of whiskey” in which of whiskey is the
object of brought (Transitive case). Moreover, the verb bring can not be used
without object.
However in “She walked (along the river)” there is no object except the activity
in parentheses (Intransitive Case).
Dependents of verb: The sub, obj and direct obj are the arguments of the verb.
Arguments centrally involved in the activity of the verb. Arguments are
expressed as NP’s, PP’s, VP’s or as clauses (that clause after verb).
Adjuncts have a less tight link to the verb and are optional, easy to move
around in the sentence. Where as complements are obligatory e.g. the object of
bring in obligatory in the above sentence. Some example of adjuncts tell us the
time, place, or manner of action or state that verb describe e.g.
a. She
saw a Woody Allen movie yesterday (time).
b. She saw a Woody Allen
movie in Paris (place). c. She saw a Woody Allen movie with great interest
(manner of action).
Subordinate Clauses (Sentences within a sentence): can also be adjuncts or
subcategorized arguments. Sometime it is difficult to distinguish adjuncts and
complements e.g. “she put the book on the table” here put forces the PP’s as
complement and “he gave his presentation on the stage” here adjunct is
optional. Some examples of subcategorized arguments are given in fig as.
Similarly subcategorization frames is particular set of argument that a verb can
appear with. It tells us the syntactic regularities about complements and also
semantic regularities e.g. bark prefers dogs as subject and verb eat prefers
edible things as objects. Some subcategorization frames are listed in fig as
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3.2.3: X Theory
• Due to limitation of phrase
structure w.r.t. systematicity and
regularities to construct phrase
and appearance of dependents
in clauses. An idea of head of
phrase is floated in modern
syntax.
• A head forms small constituent
with its complements which can
be modified by adjuncts to form
a bigger constituent and finally
combine with specifier( a sub or
sth else determiner) to form a
maximal phrase as shown in
example 3.64
This general pattern of constituency is repeated across phrase types. This is
Known as X’ theory. Where X represents variable across lexical categories.
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3.2.4 Phrase Structure/Syntactic
Ambiguity:
• Different parses for a particular sentence
is known as phrase structure ambiguity
VP makes
(already discussed a lot in previous
statement about the
lecture and CL).
instrument spoon
Children used a
• Attachment Ambiguity & Semantics:
while eating
phrases generated from two spoon
different
the cake
nodes. Different attachment have
different meaning as shown in fig 3.2
• Garden Pathing: A garden pathing leads
you along a path that suddenly turns out
not work e.g. “The horse raced past the
NP makes
barn fell”.
statement which
• First Meaning of above example
is “the
cake was eaten
horse ran past the barn (area of
storage
i.e. cake with a
of wheat)” and second is “the horse
fell
spoon and not
(close, bandhna) after it had been raced
icing
past the barn
• Garden pathing is not problem in spoken
language due to speaker’s
communicative maxims (sensible
behavior) and intonational pattern (rise
and fall in spoken) and others like that.
• What are the reasons if sentence will
have no parse at all?
Garden pathing is the phenomenon of
first being tricked into adopting a
spurious parse and then having a
backtrack to try to construct the right
parse
1.The rule does not exists
2. Ungrammatical sentence 11
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3.3: Semantic and Pragmatics
Semantic: The study of meaning of words, construction and utterances.
Divided into lexical semantic (individual word) and larger unit semantic
(combination of words).
We can organize words into lexical hierarchy as in WordNet for lexical
semantics such as antonym, synonym etc.
Hypernym or hyperonym is word with more general sense e.g. animal is a
hypernym of cat.
Hyponym: word with more specialized meaning e.g. cat is hyponym of
animal.
Meronym: part-whole relationship of word e.g. tire is meronym of car, leaf is
meronym of tree. And holonym is opposite of meronym contains whole
corresponding to a part.
Others can be seen in book. Also covered in CL
Natural language does not hold principle of compositionality, so assembling
the meaning of whole sentence from the individual sentence is hard
problem e.g. white refers to very different color in white paper, white hair,
white skin, white wine. Here is meaning include meaning of the part and
some additional semantic component that can not be predicted from the
part.
Idiom: meaning of word and meaning of phrase is completely opaque
(difficult to understand) e.g. to kick the bucket (mean dying) and carriage
return.
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Scoping problem with quantifiers and operators e.g. “everyone did not go to
the movie” when quantifier having scope over not then it means that not one
person went to movie and in contrast at least one person did not go to the
movie.
After word and sentences, the next larger unit is the discourse. Narrative
Discourse (sentence is examined to be example, elaboration, restatement)
and Conversation Discourse (model relationship between turns and kinds
speech acts (question, statements, requests, acknowledgement etc.)
Problem of anaphoric relation (relation b/t NP refers to the same thing or
person) in discourse analysis e.g. “Mary helped peter get out of the cab. He
thanked her”.
Anaphoric relations are important for information extraction as clear in
example 3.72
Pragmatics: the study of how knowledge about the world and language
conventions interact with literal meaning. Anaphoric relations are pragmatic
phenomenon e.g. to resolve the relation in discourse 3.72 , it is necessary
to know the hurricanes are disasters. SNLP did not give much attention to
pragmatics due to its complexity and lack of training data. Two areas of
pragmatics in which work started is resolution of anaphoric relations and
modeling of speech acts.
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3.4: Other Areas
• Linguistic is subdivided into phonetics (physical sound of language),
phonology (structure of sound system), sociolinguistics (interaction
of social organization and language), historical linguistics (change of
languages over time), linguistic typology (languages make different
use of linguistic devices and how they are classified as per their
use), language acquisition (how children learn language),
psycholinguistics (focus on real time production issues and
perception of language and representation of language in brain),
Mathematical linguistics (non quantitative mathematical methods).
3.5: Further Readings
• References from the book
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Questions,
Discussion
and
Comments
are
Welcomed
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