1Class 1a.Introduction to the enterpriseCAS LX 522Syntax ISome things we know! Is this English?! The cat slept.! Slept the cat.! Cat slept the.! Cat the slept.! Why?The task! What do we know?! The comes before cat, cat comes before slept.! Try to generalize.! Slept is the verb, maybe this holds of all verbs.! The cat is the subject, maybe this holds of all subjects.! Subjects contain the and a noun, with the first.! An English sentence has a subject followed by a verb.! Formalize (make precise)! Nouns: cat, dog! Verbs: slept, yawned! [Sentence [Subject the Noun ] Verb ]The task! Check:! [Sentence [Subject the Noun ] Verb ]! The cat slept.! The dog yawned.! The cat yawned.! The dog slept.! Look at further data (predictions):! The cat chased the dog.! This is an English sentence, but our schema cannot produceit. Our “theory of English sentences” is insufficient. Weneed to revise/extend it.The task! Consider the counterexample (or the classof counterexamples) to understand wherethe current theory falls short.! The cat chased the dog.! The dog is probably the same kind of thing as the cat, butwe don’t want to call it a “subject” (it’s traditionally calledthe “object”).! It contains the and a noun, and the noun seems to be themost important part.! Since it contains more than one word, we can call it a“phrase”—it’s not a whole sentence, but it’s more than aword.! So, we’ll call it a “noun phrase.”The task! Consider the counterexample (or the classof counterexamples) to understand wherethe current theory falls short.! The cat chased the dog.! In this English sentence, there is a noun phrase both beforeand after the verb. So, in addition to our previous schema,we add a second one.! Theory of English sentences:! [Sentence [NP the Noun ] Verb ]! [Sentence [NP the Noun ] Verb [NP the Noun ] ]2Lather, rinse, repeat! And the process continues.! The cat chased a dog.! A cat chased the dog.! A cat chased a dog.! It looks like a NP can either have the or a as its firstelement. Thus:! Theory of English sentences:! [Sentence [NP the Noun ] Verb ]! [Sentence [NP a Noun ] Verb ]! [Sentence [NP the Noun ] Verb [NP the Noun ] ]! [Sentence [NP the Noun ] Verb [NP a Noun ] ]! [Sentence [NP a Noun ] Verb [NP the Noun ] ]! [Sentence [NP the Noun ] Verb [NP a Noun ] ]Generalizing! What we’ve ended up with is a bit clumsy,but we can now generalize our schemas tomake this more compact:! [NP the Noun ]! [NP a Noun ]! [Sentence NP Verb ]! [Sentence NP Verb NP]! Not only does this reduce the amount we have to writedown, but it actually makes a more profound prediction: Ifthis much of our theory of English sentences is right, thenanything that can be a noun phrase subject can also be anoun phrase object. This is not just making our notationmore compact, but it is a substantive addition to the theory.Compacting the notation! There are some further ways we canconsolidate our theory of English sentencesby using some common notational tools.! X is optional: (X)! Either Y or Z: {Y/Z}! Thus:! [Sentence NP Verb (NP) ]! [NP {the/a} Noun ]! Unlike our introduction of a separate schema for NP, thischange is not a substantive change to our theory of Englishsentences, it is just a shorthand for the same theory.The grumpy cat! As a demonstration of the benefit ofintroducing a separate NP schema,consider:! The grumpy cat chased the unhappy dog.! How can we extend our theory of Englishsentences to allow for this sentence? Whatother word sequences are predicted to beEnglish sentences? Are they?Now, what are we doing?! Ok, so we have the beginnings of a theory ofEnglish sentences. But what is it?! As we’ve developed it, it is a description of sentences of English,what we might need if we wanted to program a computer toproduce English sentences.! But it is also a subset of what English speakersknow about English.! You may or may not have previously thought about the fact thatsubjects precede verbs and objects follow verbs (or the analog inyour native language), but you knew it nevertheless. You couldidentify sequences of words that did not have this property as notbeing part of your language, but it’s tacit knowledge. As such, wehave to study this knowledge indirectly, based on what are judgedto be valid sentences and what aren’t.What English speakersknow about English! An English speaker has a complex system ofknowledge that allows him/her to distinguishbetween sentences of English and non-sentences of English. We’ll refer to thissystem as a grammar. At its simplest, agrammar is a means of deciding whether asequence of words is grammatical (e.g., asentence of English) or not. We’re studyingthe properties of that system.! It’s not always obvious what it is that is wrong with non-sentences, but still the judgments (intuitions) are clear.3Types of (un)acceptability! *Big that under staple run the jump swim.! *The dog are snoring.! These are ungrammatical—there is a problem with theirform, they are not English. We write * to indicate this.! My toothbrush is pregnant again.! This is nonsensical, given our knowledge about the world(not about English), but it is grammatical.! As I knitted the sock The horse racedfell to the floor. past the barn fell.! The rat the cat the dog chased caught escapedadeptly.! These are interestingly difficult to parse but once you “getit,” they are fine (if clumsy) sentences of English.Parentheses and optionality! In describing data, people will often use the (), {}shorthand notation to indicate optionality oroptions:! Pat (quickly) ran to the bank.! Pat ran to the bank. Pat quickly ran to the bank.! Pat washed (*quickly) the asparagus.! Pat washed the asparagus. *Pat washed quickly the asparagus.! The dish ran away with *(the) spoon.! The dish ran away with the spoon.! *The dish ran away with spoon.! The cat chased {a/the} dog.! The cat chased a dog. The cat chased the dog.Ambiguity and stars! Sentences can be ambiguous.! I sat by the bank.! Sometimes we might have reason to expectambiguity that is not there, which is alsoindicated using *, on a disambiguatingcontinuation.! How did John say Mary fixed the car?! With a wrench.! In a high-pitched voice.! How did John ask if Mary fixed the car?! *With a wrench.! In a high-pitched voice.Knowledge of language is actuallyreally complicated! Bill told her mother that Mary is a genius.! Bill told her that Mary is a genius.! I told Mary that Pat gave a book to me.! Who did I tell that Pat gave a book to me?!
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