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1、转换生成语法的发展过程,Introduction,The Independence of Grammar grammatical grammatical + meaningful Tom loves Mary. grammtical, non-meaningful Colorless green ideas sleep furiously. ungrammatical ungrammatical, meaningful Which artists did you find works by interesting. ungrammtical, non-meaningful Furiously
2、sleep ideas green colorless.,The fundamental aim in linguistic analysis,Separate the grammatical sentences from the ungrammatical sentences. Study the structure of the grammatical sentences. The grammar of a language (L) will be a device that generates all of the grammatical sentences of L and none
3、of the ungrammatical ones.,Three models for the structure of a language,Finite State Grammar Phrase Structure Grammar Transformational & Generative Grammar,Finite State Grammar,Suppose we have a machine (the speaker) That has a finite number of different internal states - an initial state a final st
4、ate. That switches from one state to another by producing a symbol. That begins in the initial state, runs through a sequence of states and ends in the final state.,The man comes. The men come. State Diagram,Finite State Grammar,The,come,comes,man,men,Each node in the diagram corresponds to a state.
5、,final state,initial state,Language produced by such a machine is called a finite state language. Machine that produces such a language is called a finite state grammar (FSG). FSG is the simplest type of grammar which, with a finite amount of apparatus, can generate an infinite number of sentences.,
6、Finite State Grammar,Properties of Finite State Grammars,Such grammars allow transition from one state to another. Each state represents the grammatical restrictions that limit the choice of the next word. Machines that produce languages in this manner are also known as “finite state Markov processe
7、s”.,Problems with FSGs,不能处理非连续出现的句子成分间的关系； The old man comes. 不能反应非相邻成分间的依存关系； What does the old man speak? 有限的意味着规则不能重复使用，会导致语法系统过于复杂。,Phrase Structure Grammar,It builds up phrases out of words and put the phrases together into sentences. The kind of structural description assigned by a phrase-stru
8、cture grammar is, in fact, an immediate constituent analysis of the sentence. It assigns to each sentence that it generates a structural description. It makes use of phrase structure rules.,An example of a Phrase Structure Grammar,The child found the puppy. An example of a PSG (associated with const
9、ituent analysis) :,(1) S NP + VP (2) NP Det. + N (3) VP Verb + NP (4) Det. the, a, . (5) N. child, puppy, . (6) V. found,Representation using a Tree Diagram,S,NP,VP,The,child,Det.,N,the,V,NP,Det.,N,puppy,found,Inadequacies of PSG,Although Chomsky found phrase-structure grammar to be necessary, he ar
10、gued that this was not sufficient. 1. It under-generates i.e. fails to generate all the grammatical sentences of the language. He burst into a loud cry and left the room. The man was bitten by the dog. Did the dog bite the man? Was the man bitten by the dog? 2. It over-generates. It blindly allows m
11、any sentences as grammatical which are in fact ungrammatical. *The boy died Bill. *The men would put the book. 3. Not all cases of ambiguity are accounted for by such Grammar. 4. To account for such phenomena, the grammar must also include special transformational rules that grab phrases or pieces o
12、f phrases and move them around in specified ways.,Transformational and Generative Grammar,A Generative Grammar is a set of formal rules that can generate an infinite set of sentences that constitute the language as a whole. Chomsky insisted that a grammar - Must systematically describe all of the se
13、ntences in a language that a native speaker would regard as grammatical. Must sort out all of the possible good sentences from all of the possible bad ones. Must use a finite set of rules. Must provide a way to account for our perceived ambiguity of certain sentences.,五个发展阶段,Classical Theory（古典理论时期）
14、,时间：1957-1965 代表作：Syntactic Structure （句法结构，1957） 主要运作手段：结构转换 转换的概念：同一个句子派生过程中的运作方式。 转换运作的对象：现成的句子 短语结构规则，负责生成现成的句子 转换规则，负责改造现成的句子 派生过程=生成+转换,结构部分,基础部分,转换部分,形态音位部分,有音位值的句子,Classical Theory（古典理论时期）,词汇,形态标志,标点符号,基本材料,短语结构规则：改写规则,基础结构,转换规则,经转换后的句子,形态音位规则,例句：Tom loves Mary.,结构部分,基础部分,转换部分,形态音位部分,有音位值的句子
15、,词汇: Tom ,love, Mary,形态标志: -s,标点符号: .,基本材料,短语结构规则：改写规则,基础结构: Tom -s love Mary,转换规则,经转换后的句子： Tom love -s Mary,形态音位规则: lovelv+-ss=lvz,Tom loves Mary.,古典理论存在的问题,1.乔姆斯基的规则在生成规范句子的同时也生成不 合格的句子。 Eg: 用SNP+VP,VPV+NP两条规则,我们可以 得出John drinks wine.和Wine drinks John,这 说明动词和名词之间有一定的选择限制. 2.转换规则的力量过大，一个普通的句子可以随意 地
16、被改变，得不到任何限制。 比如John married Mary 和Mary was married by John的意思完全不同.,Standard Theory（标准理论时期）,时间：1965-1970 代表作：Aspect of the Theory of Syntax（句法理论面面观，1965） 三大部分： 基础部分：包括短语结构规则、词库和词汇搭配规则。 语义部分：在深层结构层次上做出语义表达 语音部分：对表层结构做出语音表达,结构部分,基础部分,转换部分,形态音位部分,有音位值的句子,词汇搭配规则次范畴,深层结构,语义表达式,表层结构,语音形态 表达式,词汇插入规则,投影规则,音系规则,词汇,形态标志,标点符号,短语结构规则：改写规则,转换规则,形态音位规则,词 库,标准理论时期,短语结构规则,词汇搭配规则,深层结构,词库,语义表达式,表层结构,语音形态 表达式,词汇插入规则,投影规则,转换规则,音系规则,基础部分,标准理论时期,标准理论的重大改
