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Words and rules Linguistics lecture #2 October 31, 2006 1 Overview • The atoms of language (words) • How grammar works • The grammar of sentences (syntax) 2 Words are amazing • Words are symbols: they represent things, rather than being associated with things. 今天太冷 … 不是，太熱。 This common kind of mistake shows that words are linked to symbolic forms in the mind, not physical sensations (e.g. HOT = NOT_COLD) 3 Words are amazing • Words are memorized, but people are amazingly good at memorizing them Children learn about 8 new words every day! Adults (whether English or Chinese speakers) know about 60,000 words!!! • Chimpanzees can be trained to use at most 180 words (but do they really use them symbolically, and in the correct form?) 4 Is the word learning ability innate? • Philosopher W. V. O. Quine supported behaviorism, and at first thought that words could be learned purely by association. RABBIT • Problem: How do we know what to associate with what? 5 The “gavagai” problem • Your native guide points to a rabbit and says “gavagai”. What does “gavagai” mean? GAVAGAI! 6 Words act like atoms • Words act like atoms in sentences: fundamental units that can be combined in different ways without changing their memorized value. The dog bit the man The man bit the dog 7 Atoms are combined by rules • Not every combination is grammatical (ungrammatical items are marked *) The dog bit the man The man bit the dog *The bit man the dog *Man the bit dog the 8 Syntactic classes are syntactic • Nouns and verbs are defined by their syntactic behavior, not by their meaning James likes to do research on language. (noun) James likes to research language. (verb) 9 Syntactic rules • Syntactic rules not only refer to classes, but also refer to structure (1) a. b. The boy is eating. Is the boy eating? Structure-free rule (WRONG): Move the first IS (2) a. b. c. The boy who is here is eating. *Is the boy who here is eating? Is the boy who is here eating? Structure-based rule: Move the “main” IS 10 Syntactic structure • If there is no syntactic structure, words could just be put together in a chain 那 狗 隻 這 我 和 貓 愛 。 你 11 Problems with chain hypothesis • Word-by-word associations grammatical Colorless green ideas sleep furiously • Long-distance dependencies: words can depend on each other even if far apart. 那隻很可愛的狗愛我。 那個很可愛的人愛你。 12 Syntactic rules • Since Chomsky (1957), most linguists believe that there are two basic kinds of syntactic rules rules that build sentence structure rules that change sentence structure 13 Building sentence structure The boy who is here is eating [[The boy [who [is here]]] [is eating]] 14 How do we know trees exist? • Meaning is affected by syntactic structure an egg of a beautiful bird 漂亮 的 小鳥 的 蛋 a beautiful egg of a bird 15 How do we know trees exist? • Other tests don’t refer to meaning It’s easier to pause between groupings (phrases) Rules usually move whole phrases, not parts Words like “and” join phrases of the same type James and the elephant with a purple hat are eating 16 Phrase structure rules • Chomsky’s “computer-like” formalism for building trees uses rules like these: S NP VP (a sentence contains a noun phrase plus a verb phrase) NP (Det) (Adj) N (a noun phrase contains optional determiner, e.g. the, plus optional adjective, plus a noun) VP (Adv) V (NP) (a verb phrase contains an optional adverb, plus a verb, plus an optional noun phrase) 17 Different grammars, different rules • Some English phrase structure rules S NP VP VP (Adv) V (NP) NP (Det) (Adj) N (that S) • Some Chinese phrase structure rules S NP VP VP (Adv) V (NP) NP (Det) (Adj) (S 的) N 18 Phrase structure rules aren’t enough • Find the last word in the following sentence: (1) What structure does this sentence have? • Is the last word have? But normally have must be followed by an NP: (2) a. b. *This sentence has. This sentence has structure. 19 Deep structure? • Even stranger, it’s ungrammatical to add an NP after have in sentence (1), as if something is “already there”: (3) *What structure does this sentence have structure? • Chomsky concluded that sentences like (1) are built using rules that change some deep structure into the surface structure that we actually see and hear. 20 Deep structure and surface structure • Sentence (1) would be derived like this: Deep: Surface: this sentence have what structure what structure does this sentence have • Here it is, step by step: what structure does this sentence have what structure 21 Transformation rules • In Chomsky’s theory, transformation rules change deep structure into surface structure • Deep structures are NOT “sentences” this sentence have what structure • Transformations need not happen in “real time” Generative grammar describes competence, not performance 22 Why should we believe this? • Different deep structures may be related to different meanings (4) a. Why do you think that James is dumb? b. Why do you think that James is dumb ? • There is even some performance evidence from experiments for these gaps. 23 Different grammars, different rules • An English transformation rule wh-movement: Move wh-words to the beginning • A Chinese transformation rule topicalization: Move topics to the beginning Deep: 你看過了今天的報紙嗎？ Surface: 今天的報紙你看過了 嗎？ 24 Constraints • Grammars don’t have only rules, but also constraints: principles that mark forms as good or bad rather than changing them (5) a. She likes to eat [ cake and ice cream ]. b. *What does she like to eat [ cake and ]? Constraint: An NP cannot contain a gap. 25 Summary of Chomsky’s views • Human grammar (e.g. syntax) consists of atoms (words) rules and constraints • • • • The rules and constraints operate on classes They refer to structure The ability to learn words and rules is innate The constraints are innate and don’t have to be learned at all 26 Is Chomsky right? • Many people question Chomsky’s views Are “words” and “rules” really so distinct? Must rules operate on whole classes, or can they be specific for specific words? Is structure really so important? How much of this really must be innate? 27