Rules, Movement, Ambiguity Ling 001: Syntax II Rules, Movement, Ambiguity

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 We will also look at structural ambiguity

Reviewing…. Remember that in the last lecture we developed some basic notions about constituency. Let’s apply these to sentences. Consider: The boy kicked the ball We have three lexical categories here; the nouns boy, ball, and the verb kick This gives us three phrases: two NPs, (subject and object), and one VP (headed by kick) Determining how these phrases are organized into the sentence involves the same reasoning we applied above

Possible structures In principle, the three phrases could be arranged in two ways; this is exactly parallel to what we did with words before (I’m using ‘S’ here as the label for ‘sentence’): Structure 1 Structure 2 S S VP VP NP V NP NP V NP the boy kicked the ball the boy kicked the ball

The options The different structures take different positions on the status of the VP; is it The object and verb that form a VP, or The subject and verb that form a VP? We can use the diagnostics above to give us an answer

Tests Substitution: John ate an apple. Mary did too. Did = <ate an apple> Verb + Object behaves like a constituent Movement: Mary said she would fix the car with a wrench …and [fix the car with a wrench] she did  Tests indicate that Verb + Object behave like a constituent (structure 1)

Rules… The review we just did gives us a natural transition to our next topic Recall that one of the things that we have to account for in syntactic theory is how language makes infinite use of a finite number of words We’ll see how this can be done using a basic grammar. Although our grammar will be a toy, even simple tools like this suffice to illustrate the main point

What we need We’re going to assume, as we’ve said, that there are A set of words, which belong to different categories; and A set of rules, that account for how phrases are built For the first part, let’s take some nouns, verbs, determiners, and adjectives: Nouns: cat, boy, book, burrito Verbs(transitive): eats, reads, pets Determiners: a, the Adjectives: orange, small, stubborn, purring These words will be the bottom elements (terminals) in our syntactic trees

Some Rules We can use simple phrase structure rules to give us the basic trees we will work with Remember above that the verb forms a constituent with the object; this suggests that our starting rule should be: S --> NP VP Semi-formally, the symbol S (for “sentence”) is expanded into a Noun Phrase and a Verb Phrase We need to keep working until we have all terminals (words); this means we need rules for expanding the VP and the NP

Verb Phrase For our example, take the following rule for the VP: VP --> V NP I.e., a Verb Phrase expands into a Verb and a Noun Phrase We now have two noun phrases to deal with For the V part, take V --> {eats, reads, pets} When we reach one of these words for the V, we’re done with that branch

Noun Phrases Now, let’s talk about Noun Phrases (NPs). These have (among other properties) the following: The optional presence of a 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 --> (det) 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; assume AP --> A From this rule, and rules that say ‘N-->cat,…’, A --> ‘orange, small, stubborn, purring …’, we can generate a number of phrases

Examples From N --> (det) AP* N NP det AP AP N A A the small purring cat

Lots of sentences Even with the limited vocabulary we have, and these simple rules, we generate a lot of sentences; e.g. A small boy pets the orange cat. The orange cat eats the small burrito. The stubborn boy pets the orange book. And many others (think about it…) Two additional points One about sentences that are ungrammatical/make no sense One about making the grammar put sentences within sentences

First… Two types of sentences generated by our grammar that are deviant Type 1 (morpho-syntactic?): *Boy reads the orange book. *The small cat eats book. *The cat eats a orange burrito. Type 2 (semantic?) The purring orange burrito reads a stubborn boy. Many, many more like Type 2. Also some unclear cases; e.g. The orange stubborn cat… As you can see, such a grammar generates a number of sentences that are deviant in some way. We either need to fix the grammar so that it doesn’t do this, or attribute the deviance to e.g. semantics.

Second… Our rules above do not allow us to have sentences within sentences. A simple change fixes this: VP --> V+ CP Where V+ --> {say, know, that}; and CP --> Comp S Comp --> {that} With this addition, VPs can have verbs that take a sentence inside of them It is now possible to derive The cat knows that a boy said that the burrito thinks that….

Interim As you can see, simple grammars can be extremely powerful. Syntactic theory tries to get the right balancer of power and constraints to account for people’s syntactic competence. In our examples, above, we derived basic syntactic structures A complication to this picture is found in the fact that languages seem to move constituents from one place to another (Remember our first discussion of question formation)

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 Intransitive verb: sleep One argument 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 normal, active sentences in English The agent is the subject The patient is the object There are not verbs blick like kick where this relationship is reversed

Further points In the examples above, there is a correspondence: Agent/Subject, Patient/Object One case where this is not found is in passive sentences Consider The boy kicked the ball The ball was kicked by the boy In the passive, the Agent and the Patient are the same as they are in the active But the syntactic positions are different; in particular The Patient of the verb is in the Subject position The subject in English appears in a specific position in the clause, and e.g. controls agreement on the verb

Verbs and Arguments 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 t(race)

Other cases of movement The same principle applies in other areas as well: Questions John ate the apples. What did John eat t Relative clauses John was talking to Mary. The woman [who John was talking to t] Topicalization John likes these apples. These apples John likes t.

Movement, cont. What does movement allow us to say? Uniformly, verbs look for their arguments in particular places These arguments are interpreted by fixed rules; e.g. ‘objects are patients’ Even when the surface order of constituents does not match this underlying design, the same rules apply (as long as we have traces) Sometimes the original structure is called D-structure, while the derived structure is called S-structure (think ‘deep’ vs. ‘surface’: Example: D-Structure: John ate what S-Structure: What did John eat t?

Other examples In the examples above, it’s mostly objects that are moved. But this is not always the case; consider: John said Bill fixed the car. Who did John say t fixed the car? Or John fixed the car [with a wrench]. How did John fix the car t? We’ll try to use simple examples when asking you to find traces. Remember, the best method is to put things “back into the regular order”, this should allow you to see where the trace is…

(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: John saw the man with the telescope Reading 1: John used a telescope Reading 2: The man John saw had a telescope

(Structural) Ambiguities Notice that both NPs and VPs can have PPs attached to them We could do this with rules like VP --> VP PP, NP --> NP PP 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: John saw the man with the telescope Reading 1: John used a telescope Reading 2: The man John saw had a telescope