Transcript Ling 001: Syntax II

Ling 001: Syntax II
Movement & Constraints
2-11-2009
Phrases
• In the last lecture, we talked about simple phrases;
e.g. Noun Phrases like
– The dog
– The big dog
– The big dog that John was talking to
• In this lecture, we will look at how phrases and larger
objects are derived by rules, and how phrases can be
moved from one position to another
– How structures and meanings (including ambiguity) are
mediated by syntax, particularly those “hidden” structures
that we don’t see or hear but actually use
– “John is easy to please” vs. “John is eager to please”
– Some basic rules and two case studies of hidden structures
that combine linguistics with psychology
Notations: Noun Phrase Example
• Let’s talk about Noun Phrases (NPs) to begin with. These have
(among other properties) the following:
– The optional presence of an determiner (‘the’, ‘a’, etc.)
– The optional presence of more than one adjective
• We can write a rule that generates NPs in the following way:
NP --> (determiner) AP* N
This means that a noun phrase consists of minimally a head N; it also
can have
-an optional determiner (parentheses)
-any number of Adjective Phrases (AP), including zero
• From this rule, and rules that say ‘N-->cat,…’, A --> ‘big, furry,
irritable…’, we can generate a number of phrases
Examples
• From N --> (det) AP* N
NP
det
the
AP
AP
A
A
big
furry
cat
N
Adjuncts (are optional)
• We also need a way of adding adjoined
phrases like in [the cat [in the hat]].
• The PP here is adjoined, to “modify” the
meanings of the NP. The object that it is
attached to is still an NP.
• The rule that we can talk about is like this:
NP --> NP PP (the cat in the hat)
There are other options for this, but this will generate
the right structure, along with one more rule:
PP --> P NP (in the hat)
Verb Phrases
• We will also need rules to derive VPs
• Consider:
VP --> V NP
This says that a VP consists of a V and an NP
• This will define our set of transitive verbs: those that
have objects (more on this in a few slides)
• To be explicit, we could indicate this as
VP --> V-trans NP
Where
V-trans --> kick, hit, kill, ….
We want to exclude V’s like sleep, arrive, etc. from this
context
More Verb Phrases
• We can also have a PP adjunct to a verb
phrase; often these specify how the action
was performed, where it was performed, etc.
– Mary fixed the car with a wrench
– John kicked the ball in the garden
• A rule like the one that we employed above
will work here:
– VP --> VP PP
• VP--> V NP, NP->NP PP, VP->VP PP: this is
getting confusing
(Structural) Ambiguities
• Notice that both NPs and VPs can have PPs
attached to them
• In some cases, this results in what is called a
structural ambiguity: one string has more
than one structure associated with it, and
means different things depending on what the
structure is
• Example: I shot an elephant in my
pajamas.(How did it get in there I don’t know).
– Reading 1: I shot an elephant while wearing my
pajamas.
– Reading 2: The elephant I shot wore my pajamas
for some reason.
More ambiguity
• Juvenile Court to Try Shooting Defendant
• Stolen Painting Found by Tree
• Kids Make Nutritious Snacks
• Obesity Study Looks for Larger Test Groups
• British Left Waffles on Falkland Islands
• Red Tape Holds Up New Bridges
• Hospitals Sued by 7 Foot Doctors
• Bush Wins on Nomination, but More Lies
Ahead
Analysis: Recall un-lock-able
• We can understand these ambiguities in
terms of our rules above. The ambiguity
depends on whether the VP is modified by
the PP (reading2) or the NP is so modified
(reading 1)
Sentences, etc.
• In order to generate sentences, we need
additional rules
• For instance, where ‘S’ is for sentence:
S --> NP VP
• When we add rules for distinguishing
transitives from intransitives, etc., we can
derive a wide range of sentence types
Jabberwocky
• 'Twas brillig, and the slithy toves
• Did grye and gimble in the wabe:
• And mimsy were the borogoves,
• And the moeme raths outgrabe.
• What is/are “toves”? “wabe”?
• “gimble” cannot mean something like “like”.
Its syntax is intransitive, so it must involve
only one argument
Arguments, etc.
• In some sense, many things that happen in a
sentence depend on what the verb in the
sentence is:
– Transitive verb: kick
• Two ‘arguments’ of kick, like f(x,y)
– Intransitive verb: sleep
• One argument, like f(x)
• In order to be more precise about this, we
need to distinguish grammatical (syntactic)
position from semantic role
Roles and Positions
• Consider a transitive verb like kick
– This has two arguments
– The arguments are
• The agent (the kicker)
• The patient (the thing kicked)
– In active sentences in English
• The agent is the subject
• The patient is the object
Verbs and Arguments:
Introducing Movement
• Verbs are looking for their arguments in particular
positions; remember the rule we formulated above:
– Patients appear in object position (inside the VP)
• What about the passive? Here is where the process
of movement is important
• We can start with the VP [kick [the ball]].
• Then the object of the verb kick is moved to subject position as
part of the passive rule
• It is still interpreted as the Patient, because that is where it starts
• In order to be interpreted as a patient, the NP has to have some
relationship to the position where it came from; this is why
traces are important:
• [The ball] was kicked _____
Other cases of movement
• The same principle applies in other areas as well:
whenever an element appears in a position that is
NOT where it is interpreted meaning-wise
• Questions
– John ate the apples.
– What did John eat ____
• Relative clauses
– John was talking to Mary.
– The woman [who John was talking to _____]
• Topicalization
– John likes these apples.
– These apples John likes _____.
A brief look at some other
languages
• English: I always DO my homework.
•
I AM always late
• Note the difference between different kinds of
verbs
Old(er) English
Shakespeare English/French
• Basic Pattern: In French and Old English, the finite
verb appears before adverbs and negation
• In Shakespeare/French: the verb also moves in
questions
• In Modern English: only the auxiliary does so
– E.g., Do you always read the books?
Rules + transformations
• In all languages: S->NP VP, VP-> (Adv) VP
• VP->V NP, or
What does the verb go?
• In French/Old English, it moves
to a position above the adverb
but after the subject
• This is the position called
TENSE, where tense like
present/past is represented
– E.g., We like exams. We DO
like exams. We DID like
exams
– Revise the rules: S NP TP,
TP->Tense VP…
Transformations across
languages
• French/OE: main verb moves to the Tense
position
• English: main verb stays put. If TENSE needs
to be filled, we put an auxiliary there
– I DID like exams.
• In Shakespeare/French, the main verb moves
to the beginning of sentence to form
questions
• In Modern English, the main verb stays and
the auxiliary verb moves to the beginning
French/Old English vs. English
Constraints on Movements
• Much like syntactic rules, which don’t just combine
anything and everything, movement is also restricted:
some of these “traffic” laws are quite bizarre
• Recall the auxiliary movement rule (last lecture) in
English questions: no movement of the first auxiliary
• I shot an elephant in my pajamas.
– Two readings
• What (clothes) did I shoot an elephant in?
– How many readings?
Of Elephants and Pajamas
There are structures out of which movement is not possible.
And this is quite general across sentences and languages
Impossible movements, Possible
Meanings
A-over-A Principle, or No
Grandparent Left Behind
• In general, a small NP cannot move out of a
large NP.
Even young children know this
• Three year olds saw a play.
• A dog broke a leg.
• A little girl fixed it up with a bandage
• “What did she fix the puppy with ___?
• Reality gives two answers, but constraint on
movement makes only one possible--and
that’s how children answered.
Another psychological dimension
• To this point, the discussion of traces has
been motivated by considerations of how
verbs find their arguments
• A substantial research program in linguistic
theory asks further questions for other cases
that look like movement
• For an additional illustration, we will consider
here some psycholinguistic evidence about
how traces are processed online by hearers
Chains of Fillers and Gaps aka
moved elements and traces
• The idea above is that the “who” functions as
a kind of place-holder:
– The man who John was talking to ___ left.
• In this particular case, the idea is that the
who, which is associated with the man, must
be understood as the object of talking to
• Another way of investigating this hypothesis
involves priming; in the following slides, I
summarize an experiment by Swinney et al.
(1988)
Background: Lexical Access
• When we hear the sound form of a word like
cat (or see it represented in spelling) we
activate this lexical item (word); this is called
Lexical Access
• A number of factors determine how quickly
Lexical Access will occur for any particular
word
– Length
– Frequency of the word
– Etc.
Priming
• One factor that influences lexical access is called
Priming
• Priming is the facilitation of lexical access-- under
certain circumstances, accessing a word is faster
than it is in others
• Example: consider lexical access for word 2:
Word 1
Word 2
Situation 1:
cat
dog
Situation 2:
hat
dog
• In situation 1, access of dog is speeded up because
semantically-related cat is processed first (we could
say that cat primes the access of dog)
Back to traces
• What does priming have to do with traces?
Consider the following example:
The policeman saw the boy who the crowd
accused _____ of the crime
• In this example, the NP the boy is understood
as the object of accused
• This is because of movement in the relative
clause, where who moves to the front and
leaves a trace
An Experiment: Predictions
• Predictions of the model with traces:
– Meaning of boy should be active when it is first processed
– This activation should decline over the following part of the
sentence
– The item boy should be re-activated at the position of the
trace, because that is where it is understood
Activation of boy:
Active
---declining--->
The policeman saw the boy who the crowd at
Declining--->
REACTIVATED
the party accused trace of the crime
Design
• The experiment uses
– A design in which subjects are listening to sentences like the
one above
– At the point of the trace, the subjects are presented with a
word visually, which they have to pronounce aloud; this is
enough to see if there is priming or not
• Situation 1: Basic Result
– The word girl is presented at the position of the trace
– Boy and girl show a priming effect independently because
they are related
– Result: Data showed facilitated access for girl, indicating reactivation of boy at the trace position
• Situation 2: In order to confirm the above
– Other nouns in the sentence (policeman, crowd) were tested
at the trace position
– The results showed that these nouns were not activated at
the trace position
Summary
• Movement is required for cases in which constituents
appear in positions that they are not normally
associated with
• The theory posits that movement leaves a trace in
the original position, an object that relates to the
moved element
• Substantial research questions concern what moves
where, how far, etc.
• Some experimental results suggest reactivation of
moved elements at trace positions
• Syntax is the codebook that translates meanings into
structures and then backwards