Transcript Introduction to Computational Linguistics

Introduction to Linguistics II
Ling 2-121C, group b
Eleni Miltsakaki
AUTH
Spring 2006
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Course outline
• Morphology
– Content words and function words
– Bound and free morphemes
– Word formation processes
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Syntax
Semantics
Pragmatics
Historical Linguistics
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What is morphology?
• The study of the structure of
words
– Words are part of our linguistic
knowledge
– Words are part of our mental
grammars
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Basic questions for morphology
• What are words and how are they
formed?
• How are complex words formed from simpler parts?
• What are the basic building blocks in the formation of
complex words?
• How is the meaning of the complex
word related to the meaning of its
parts?
• How are individual words of a
language related to other words of 4
What do we know when we
know a ‘word’?
• Phonological info: How it is
pronounced
• Morphological info: Its
internal structure
• Syntactic info: Part of speech
• Semantic info: What it means
• Pragmatic info: How we use it
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What is a word?
• Video-show
• An arbitrary pairing of sound
and meaning
– E.g. house, casa, maison etc
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Content and function words
• Content words
– They denote concepts
– They are open class
– They are nouns, adjectives, adverbs
• Function words
– They have a grammatical function
– They are closed class
– They are conjunctions, prepositions, articles,
demonstratives, pronouns
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Simple and complex words
• Simple words
– Minimal unit
– Cannot be further analyzed
– E.g. tree
• Complex words
– Made of more than one part
– E.g. trees
 We need a name for the parts which combine to make complex words
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Morphemes
• Morphemes are the building blocks of complex
words
– ‘Trees’: base morpheme + plural morpheme
• Types of morphemes
– Free: independent words
– Bound: affixes
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Types of affixes
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Prefixes: They are attached to the beginning of another
morpheme
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E.g. rewrite, rethink
Suffixes: They are attached to the end of another morpheme
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E.g. modernize, centralize
Infixes: They are attached within another morpheme (less
common but certain languages do have infixes)
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E.g. kayu = wood
-in- = product of a completed action
kinayu = gathered wood
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How are new words created?
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Word formation rules (derivations)
Coining
Compounding
Blending
Acronyms
Clippings
Backformation
Conversion
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Derivational morphology
• Bound morphemes added to a root morpheme to form a
new word with new meaning are called derivational
morphemes.
• E.g. -ify, -cation
pure  purify  purification
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to make pure the process of making pure
“pouzy”  pouzify  pouzification
• The form that results from the addition of a derivational
morpheme is called derived word
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The hierarchical structure of
words
• Morphemes are added in a fixed order according
to the morphological rules of a language
• E.g. system  systematic  unsystematic
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Tree diagrams
• The hierarchical organization of words can be
represented in a tree diagram
Adjective
Un
Adjective
Noun
system
atic
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Adverb
Adjective
Adjective
un
ly
al
Adjective
Noun
atic
system
*unsystem
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More about trees
• Tree diagrams are the linguist’s hypothesis
of how speakers represent the internal
structure of words
• Take a look at ambiguous cases such as
unlockable
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Not able to be locked
Able to be unlocked
Adjective
Adjective
Verb
un
able
Adjective
un
Verb
verb
able
lock
lock
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• If words were only strings of morphemes
without any internal organization, we could
not explain the ambiguity of words like
‘unlockable’
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Inflectional morphology
• Inflectional morphology indicates
grammatical aspects of a word
– Plurality (boy – boys)
– Tense (walk – walked)
– Person (walk – walks)
• In English all inflectional morphemes are
suffixes
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How many morphemes?
1.
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10.
Retroactive
Befriended
Televise
Margin
Psychology
Unpalatable
Deactivation
Airsickness
Grandmother
Morphemic
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Can you “tree” the ambiguity?
A: Have you finished your ten-page book report,
Norman?
B: I haven’t even started it.
A: But it’s due tomorrow! I started mine a month
ago! Why did you wait until last minute??
B: Perhaps I have more confidence in my
intellectual abilities that you have in yours!
Besides, how long could it possibly take to read
a ten-page book?
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Coining
• Speakers invent (coin) new words to
describe previously non-existent objects
• E.g., xerox, fax, nylon, vaseline etc
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Compounding
• When two or more words are combined to
form a new word
• E.g., bittersweet, homework, spoonfeed,
sleepwalk etc.
• In English the rightmost of a compound is
the head of the compound
– Noun+verb=verb, e.g., spoonfeed
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Meaning of compounds
• The meaning of compounds is not always the
sum of its parts
• E.g. a blackboard maybe green or white
• Also
– A boathouse is a house for boats but a cathouse is not
a house for cats (slang for whorehouse)
– A jumping bean is a bean that jumps, a falling star is a
star that falls but a looking glass is not a glass that
looks
– Peanut oil and olive oil but baby oil?
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Pronunciation of compounds
• In a compound the first word is usually
stressed:
• Compare: REDcoat (slang for British
soldier) with red COAT
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Blending
• The combination of two separate forms to
produce a single new term
– Smoke + fog = smog
– Breakfast + lunch = brunch
– Motor + hotel = motel
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Acronyms
• Acronyms are words derived from the initials of
several words
– NASA, from National Aeronautics and Space Agency
– UNESCO, from United Nations Educational, Scientific,
and Cultural Organization
– Radar, from radio detecting and ranging
– Laser, from light amplification by stimulated emission
of radiation
– Scuba, from self-contained underwater breathing
apparatus
– RAM, random access memory
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Backformation
• A new word may enter the language
because of an incorrect morphological
analysis
– beggar  beg
– editor  edit
– Enthusiasm  enthuse
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Abbreviation
• Abbreviations of longer words may be
lexicalized
– Fax  facsimile
– Telly  television
– Gym  gymnasium
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Eponyms
• Eponyms are words derived from proper
names
– Sandwich: named for the fourth Earl of
Sandwich who put his food between two slices
of bread so that he could eat while he
gambled
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Clipping
• Clipping occurs when a word of more than
one syllable is reduced to a shorter form
– Fan  fanatic
– Plane  airplane
– Pro  professional
– Lab  laboratory
– Gas  gasoline
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Conversion
• Conversion is a change in the function of a
word
– Verbs  nouns (guess, must, spy, etc.)
– Adjectives  verbs (dirty, empty, total, etc.)
– Particles  verbs (up, down)
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