Transcript 5-Morphology

Morphology, Part 1
January 24, 2012
For Starters
•
The “Turing Test”
•
Conceived by the English
mathematician/philosopher
Alan Turing (1912-1954).
•
Turing developed much of the
theoretical groundwork for
modern-day computing machines.
•
He also worked on cracking
enemy codes during World War II.
• The Turing Test: don’t ask whether or not a machine can
“think”; ask whether or not it can fool someone into thinking
it’s human in a natural language conversation.
• Check out ELIZA: http://psych.fullerton.edu/mbirnbaum/psych101/Eliza.htm
The Last Quick Write!
The Last Quick Write.
Half of the Story
• First: a Simpsons-based Quick Write
• Second: remember what we learned last time…
• Human beings can be creative with language because:
• We know the rules for putting sounds and words
together to form sentences.
• Patterns (Sentence = Noun + Verb)
• Patterns of Patterns (Recursive sentences)
• These rules = the grammar of the language we know.
• Q: What else do we need to know to be a competent
speaker of a language?
The Rest of the Story
• We need to know what units can be put together by the
rules of grammar.
• Including: the units of a sentence
• color, green, idea, sleep, furious, brown, dog, odor,
bark, angry, large, lizard...
• These units = the lexicon of the language we know
• From Ancient Greek: lexikon “dictionary”
• lexis = “word”
• Remember: language is discrete.
Knowledge of Language
Grammar
Lexicon
RULES
UNITS
1) Sentence = Noun + Verb
etc.
1) ragamuffin (N)
2) rotund (Adj)
3) rutabaga (N)
etc.
What’s in the Lexicon?
• Generally speaking, the lexicon contains:
• all the words in the language you know
• the building blocks of grammatical sentences
• Note, however:
• not only do lexical items differ from language to
language: (tree, Baum, arbre)
• …but one person’s lexicon might be different from
another’s
• It also happens to be a bit tricky to define exactly what a
“word” is…
Words, words, words
• Here’s a working definition--words are the smallest free
form elements of language:
• They do not have to occur in a fixed position with
respect to their neighbors.
• Example words:
bird
cycle
talk
happy
birds
recycle
talked
happiness
“-ed”
“-ness”
• Example “non-words”:
“-s”
“re-”
• The “non-words” cannot stand on their own-• They have to be attached to something else.
Morphemes
• Words consist of one or more morphemes.
• Morphemes
• = the smallest meaningful unit of speech
• = a string of sound(s) that carries some information
about meaning or function.
• An example (non-word) morpheme: [-s] = plural marker
• Note the pattern:
bird
birds
dog
dogs
cat
cats
cow
cows
...etc.
Plural Formation
• Plural nouns in English are formed by rule:
Singular noun + [-s]  Plural noun
• So: plural nouns contain two morphemes:
• the singular noun (e.g., “bird”)
• the plural marker (e.g., “s”)
• The rule for putting them together is a word-formation
rule.
• Q: Are “bird” and “birds” two different words?
• Do we need two different entries for them in the
lexicon?
Language Model, version 2.0
Grammar
Lexicon
RULES
MORPHEMES
[bird]
Word-formation rules
Singular N+ /-s/  Plural N
[-s]
Morpheme Types
• Free morpheme: a morpheme that can stand on its own
• bird
toast
• cycle
happy
• Bound morpheme: a morpheme that must attach to
another morpheme
• -s
-er
• re-
-ness
• Another distinction:
• simple words contain only one morpheme
• complex words contain more than one morpheme
Simple and Complex
simple
complex
Language Model, version 3.0
Grammar
Lexicon
RULES
MORPHEMES
Bound
Free
Word-formation rules
Singular N+ /-s/  Plural N
[-s]
[bird]
[re-]
[cycle]
Roots and Affixes
• Bound morphemes are also known as affixes
• Affixes attach to roots in word-formation rules
• Ex. 1: “birds”
• root = [bird] + affix = [-s]
• Ex. 2: “recycle”
• affix = [re-] + root = [cycle]
• Affixes which precede the root are known as prefixes
• Affixes which follow the root are known as suffixes
Infixes
• When affixes are inserted into the middle of a root, they
are known as infixes.
Bontoc (Phillippines):
fikas “strong”
fumikas
“to be strong”
kilad “red”
kumilad
“to be red”
fusul “enemy”
fumusul
“to be an enemy”
• Can this sort of thing happen in English?
• Abso-freakin’-lutely!
• (but it’s not particularly common)
Circumfixes
• In some languages, there are even circumfixes.
• Circumfixes attach both before and after the root.
Chokma (Oklahoma)
chokma
“he is good” ikchokmo
“he isn’t good”
lakna
“it is yellow” iklakno
“it isn’t yellow”
palli
“it is hot”
ikpallo
“it isn’t hot”
“love” (root)
geliebt
“loved”
frag- “ask” (root)
gefragt
“asked”
German
lieb-
Hand in Hand
• Note: affixes are always bound morphemes.
• In English, roots tend to be free morphemes.
• However, this is not always the case-• For instance: blueberry, blackberry…
• but: cranberry, huckleberry, raspberry.
• What do [cran-], [huckle-] and [rasp-] mean?
• Bound roots in English are called cranberry morphemes
• (technical term)
Cranberry Morphemes
• Cranberry morphemes are bound root morphemes.
• They have no independent meaning.
• They also have no parts of speech
• Some deceiving examples: • Also: the liberation of cran?
• perceive, receive, deceive
• -ceive?
• infer, refer, defer
• -fer?
• commit, permit, submit
• -mit?
Conjugation
• In many languages verbs are conjugated by adding affixes
specifying person and number to a bound root form.
• Italian: parlare “to speak”
Singular
Plural
1st
Io parlo “I speak”
Noi parliamo “We speak”
2nd
Tu parli “You speak”Voi parlate “Y’all speak”
3rd
Lui parla “He speaks”
Loro parlano “They speak”
Lei parla “She speaks”
• Note: the root form /parl-/ never appears on its own,
without an ending.
Bases (or Stems)
• Once an affix has attached to a root morpheme, it forms
a base…
• to which other affixes may attach.
• Example:
• boy (root) + -ish (suffix) = boyish
• Round two:
• boyish (base) + -ness (suffix) = boyishness
• Another example: black (root) + -en = blacken
• Round two: blacken (base) + -ed = blackened
• In some linguistic circles, bases are called stems.
Lexical Categories
•
Important: we know that word-building takes place in
stages because specific affixes are particular about what
kinds of words they can attach to.
•
A quick and dirty review of lexical categories (parts of
speech):
1. Nouns
•
semantically = people, places, things
•
dog, cat, bike, person, planet, ball, etc.
2. Verbs
•
semantically = actions, sensations, states
•
run, kick, scratch, scream, bite, walk, be, have, etc.
Lexical Categories, reviewed
3. Adjectives
•
semantically = properties or qualities
•
happy, sad, angry, funny, clear, fuzzy, ugly, etc.
4. Prepositions
•
semantically = spatial relationships (pre + position)
•
to, for, of, with, out, in, above, below, etc.
5. Adverbs
•
•
semantically = properties or qualities of verbs and
adjectives
•
often, seldom, rarely, purely, frequently, etc.
We’ll talk about these again when we get to syntax…
Quiz Time
•
Which affixes are being attached in the following
sets of words?
•
Which lexical categories do those affixes attach to?
•
Which lexical categories are formed by adding the
affix?
1. uncertain, unhappy, untrue
2. exactly, profoundly, deeply
3. moralize, vandalize, sermonize
4. deconstruct, decode, derail
Layers of Words
• Words that are formed through the addition of multiple
affixes have a layered, or hierarchical structure.
• One (ugly) way to represent this structure is through
bracket notation:
• [root]
[cycle]
• [[affix] + [root]]
[[re-] + [cycle]]
• [[base] + [affix]]
[[[re-] + [cycle]] + [-ing]]
• WORD
recycling
(=base)
Tree Structures
• In this class, we’ll primarily stick with tree diagrams to
represent word structure.
• (because they look better and are easier to read)
re
cycle ing
un
desire
able
• Tree terminology: branches
• nodes: where two branches meet
• nodes represent constituents of the word
Picky, Picky
• Affixes generally attach to a base with a particular lexical
category.
• Examples:
• verb = [re-] + verb
• recycle = [re-] + cycle
• adjective = [in-] + adjective
(“to do again”)
reuse = [re-] + use
(“opposite of”)
• insecure = [in-] + secure
• incomplete = [in-] + complete
• noun = [ex-] + noun
(“former”)
• ex-wife = [ex-] + wife
• ex-president = [ex-] + president
Tricky Picky
• Other affixes attach to a base of a particular lexical
category…
• And create a word of a different lexical category.
• noun = verb + [-er]
• toaster = toast + [-er]
teacher = teach + [-er]
• verb = adjective + [-en]
• blacken = black + [-en]
freshen = fresh + [-en]
• adjective = verb + [-able]
• desirable = desire + [-able]
• squeezable = squeeze + [-able]
Building the Perfect Beasts
• To accurately capture all of the facts of word formation…
• tree structures should represent the lexical categories
of all constituents at each node in the tree.
Noun
Adj
Verb
Adj
Aff
Verb Aff
Aff
Verb
Aff
[re-]
[cycle] [-ing]
[un-] [desire] [-able]