roberts li2 michaelmas 2010, lecture 3 lecture three: phrase structure rules professor ian roberts...

Roberts Li2 Michaelmas 2010, Lecture 3

Lecture Three: Phrase Structure Rules

Professor Ian [email protected]


Introduction

We’ve seen how syntactic representations (labeled bracketings and tree diagrams) are built from categories and constituents

But we also need to specify what the bad sequences of words (and presumably structures) are:


(1) a. *Spoke John.b. *Hopes Alex that Wayne

will sign the contract.

c. *Loves the Leader of the Opposition his wife.


Phrase structure rules the formal device used to generate constituent

structure, by specifying all and only the possible ways in which categories can combine:

i. S NP VP (“Rewrite the symbol S as the sequence NP VP”)

ii. VP V (NP) (PP) iii. NP (D) N (PP) iv. PP P NP

-- these rules can generate the tree diagram/labelled bracketing we saw last time, and similar ones:


(3) S r u NP VP | r u N V PP Ron thought r u

P NP | r u about D N | | the problem


Recursion and subordinate clauses Recursion: NP can appear on either

side of the arrow in the rules in (2). This means NPs can appear inside other NPs in tree diagrams. In fact, we can keep applying rules (iii) and (iv) to their own output. This gives results like:

the height of the lettering on the covers of the manuals


The ability of rules to apply to their own output is known as recursion. This is an extremely important concept, as it gives rise to the possibility of sentences of unlimited length and underlies the fact that human languages are able to make infinite use of finite means.


Subordinate clauses: Mary hopes [ that John said something ].

i. VP V CP ii. CP C S

“C” stands for “complementiser”, an element which introduces a subordinate sentence.

We now have S-recursion, alongside NP- and PP-recursion.


S r u

NP VP | r u N V CP Mary hopes r u C S that r

u NP VP John r u V NP said | N something


Mary hopes that John expects that Pete thinks that Dave said that …

Other kinds of complementsers and subordinate clauses (CPs):

a. Mary wonders [CP whether John will say something ].

b. Mary would prefer [CP for John to say something ].


Constituency tests The PS-rule VP V NP generates the sequence V

NP, but does not generate NP V. However, we do find this sequence:

[NP The Minister ] [V denied ] the allegations.

Why don’t we say that NP and V form a constituent here? The same question could be raised about the NP P sequence in (a) or the N D sequence in (b):

a. They gave [NP the book ] [P to ] Mary.b. I know the [N girl ] [D the ] man described.


Various rearrangements can be performed on sentences. These operations affect phrasal constituents, so they can be used to show whether some sequence of words forms a phrasal constituent or not. These are the constituency tests. The most commonly used tests (for English) are:

- clefting - passivisation - pronoun substitution - fronting - WH-fronting


a. Cleftinga. The Party Chairman sent a telex to John. b. It was to John that the Party Chairman sent a telex

t.

Here to John has been clefted. The general schema for clefting is:

S It was X that S. In other words, take a sentence S and turn it into It

was X that S, where S has a gap (marked with a t in (b)) where X would normally be. Most importantly, X has to be a phrasal constituent (we could write “XP” instead of “X” to indicate this).


Here are some more cleft sentences :a. It was the Party Chairman that t sent a telex to John.b. It was a telex that the Party Chairman sent t to John. We saw that to John is a constituent, (a) shows that the

Party Chairman is a constituent and (b) shows that a telex is a constituent. Compare now:

c. *It was the Party Chairman sent that t a telex to John.d. *It was a telex to that the Party Chairman sent t John.


So we have evidence for the following tree structure:

S r u NP VP t y r u u D N V NP PP The P.C. sent t y t y

D N P NPa telex to |

N John


b. PassivisationJohn visited several towns.

Here John is the “visitor” (the Agent of the verb visit) while several towns is what is visited (the Patient of the verb visit). Agent and Patient are the thematic roles of the verb visit. Passivisation switches the positions of the thematic roles in the sentence (and makes the Agent optional):

Several towns were visited (by John). Passivisation must apply to whole NPs:

*Towns were visited several (by John).


c. Pronoun substitution Pronouns (I/me, he/him, she/her, etc.) are

noun-like elements which don’t pick out anything themselves, but stand for something else. This “something else”, known as the antecedent, determines what the pronoun picks out:

John hopes that he will win. Here John is the antecedent of he (note

that it doesn’t have to be; he could refer to someone not mentioned in the sentence).


Pronouns, despite their name (pro-nouns), stand for NPs:

a. [NP The man who wears glasses ] hopes that he will win.

b. *The he who wears glasses hopes that he will win.

c. He hopes that he will win.


Other categories have pro-forms. Most VPs can be replaced by do so:

Dave [ promised everyone a tax cut ], and Vince did so too.

Again, the whole VP must be substituted:

* … , and Vince did so everyone a tax cut too.


d. Fronting This operation emphasises (topicalises) phrasal

constituents:a. Mary hopes that John will like her friends.b. Her friends, Mary hopes that John will like t.c. That John will like her friends, Mary hopes t.d. (Mary hoped that John would like her friends) …

… and [VP like her friends ] he did. Three things to note: i) (c) shows that CP is a constituent. ii) Fronting leaves a gap (t) too. iii) did appears again in (d).


e. WH-Fronting Another type of fronting involves a phrase

containing a WH-word (who, what, why, when, where, how, etc.). There is a gap in the position where the WH-phrase “should” be. WH-Fronting makes a sentence into a question:

a. Which friends does Mary hope that John will like t ?(Mary hopes that John will like WHICH friends??!!)

b. What did the Party Chairman send t to John?c. Who did the Party Chairman send a telex to t ?d. To whom did the Party Chairman send a telex t ?


Structural ambiguity John saw the man with the binoculars.a. John saw [NP the man [PP with the binoculars ]].b. John saw [NP the man ] [PP with the binoculars ].

c. It was the man with the binoculars John saw t.d. It was the man John saw t with the binoculars.

You can apply the other tests in the privacy of your

room (or supervision).

roberts li2 michaelmas 2010, lecture 3 lecture three: phrase structure rules professor ian roberts...

Documents

sequence v np

s np vp

np p sequence

problemroberts li2 michaelmas

manualsroberts li2 michaelmas

sequence np vpii

pp p np

psrule vp v np