<thead id="t1bbr"><dfn id="t1bbr"></dfn></thead>

    <nobr id="t1bbr"><cite id="t1bbr"><menuitem id="t1bbr"></menuitem></cite></nobr>

    <form id="t1bbr"></form>

      <em id="t1bbr"></em>

      18210244181 | 登錄 注冊
      發布時間:2019年07月01日     發布人:nanyuzi  
      字號 簡體 繁體 打印


      (T) 轉換


      A formal linguistic operation which enables two levels of structural representation to be placed in correspondence. A transformational rule (T rule, transformation or transform) consists of a sequence of symbols which is rewritten as another sequence, according to certain convention. The ‘input’ to the rule is the structural description (‘structural analysis’ or ‘structure index’), which defines the class of phrase-markers to which the rule can apply. The rule then operates a structural change on this input, by performing one or more of several basic operations. Movement (reordering or permutation) transformations modify an input structure by reordering the elements it contains. When this operation is seen as one of moving elements to adjoining positions in a phrase-marker, it is known as adjunction. Insertion transformation add new structural elements to the input structure (as in element-copying, or the insertion of by in the passive transformation below). Deletion transformations eliminate elements from the input structure.

      One of the earliest illustrations of the operation of a transformational rule was the one which converted active sentences into passive ones, which can be formulated as follows:

      NP1 - Aux -V - NP2→NP2 - Aux + be + en - V - by + NP1

      (where be is a form of the verb to be, and en represents the past-participle ending of the lexical verb). The rule is said to ‘operate’ on the first, underlying phrase-marker, converting it into a second, ‘derived’, phrase-marker. The string produced by the derived phrase-marker may then serve as the underlying string for further transformations, as the analysis of the sentence proceeds. The sequence of phrase-markers assigned to a sentence constitutes its transformational derivation or transformational history.

      A grammar which operates using this notion is a transformational grammar (TG) or transformational generative grammar (TGG). This type of grammar was first discussed by Noam Chomsky in Syntactic Structures (1957) as an illustration of a generative device more powerful than finite-state grammars or phrase-structure grammars. In this view, very many sentence types can be economically derived by supplementing the constituent analysis rules of phrase-structure grammars with rules for transforming one sentence into another. Transformational grammars became the most influential type in the development of generative grammatical theory: indeed, the field as a whole for a time came to be variously known as ‘generative grammar’, ‘transformational-generative grammar’ (or simply ‘TG’).

      Several models of transformational grammar have been presented since its first outline. The standard model, as presented by Chomsky in Aspects of the Theory of Syntax (1965), consisting of three components: (a) a syntactic component, comprising a basic set of phrase-structure rules (sometimes called the base component), which together with lexical information provides the deep-structure information about sentences, and a set of transformational rules for generating surface structures; (b) a phonological component, which converts strings of syntactic elements into pronounceable utterance; and (c) a semantic component, which provides a representation of the meaning of the lexical items to be used in the sentence. The ways in which these components should be interrelated (especially the relationships between semantics and syntax) have proved to be a source of continuing controversy, since the appearance of Aspects, and alternative models of analysis have developed (compare especially the distinction between generative and interpretive semantics).

      As a result of these developments, the status and classification of transformations varied a great deal in the 1960s and 1970s. A distinction introduced early on is that between optional and obligatory transformations, and the former referring to a rule which may apply at a given stage in a derivation, the latter to a rule which must apply, if a well-formed sentence is to result. On the other hand, the classification and terminology of transformations in Syntactic Structures is different in many respects from that encountered in Aspects. In the former, two types of transformation are recognized: singulary (or single-base), where the rule operates on only one terminal string; and generalized, where the rule combines two or more terminal strings, as in conjoining and embedding transformations (which handle co-ordination and sub-ordination respectively). In Aspects, however, other distinctions are introduced, some of which replace those found in the former book. Of particular importance is a distinction drawn in one of the models outlined in Aspects between lexical and ‘non-lexical’ transformations: the former transform pre-lexical structures into deep structures containing complex symbols; the latter transform deep structures into surface structures. A further development is the much increased generality of transformations, culminating in the rule ‘move alpha’ - essentially a licence to move anything anywhere, except that the movement must be an instance of either substitution or adjunction, and must obey subjacency. 




      NP1 - Aux -V - NP2→NP2 - Aux + be + en - V - by + NP1

      (其中be是動詞to be的一種形式,en代表詞匯動詞的過去分詞詞尾。)按理論,這條規則“作用”于第一個即底層的短語標記,將其變接成第二個即“派生”的短語標記。由該派生的短語標記產生的語符列然后又可隨句子的進一步分析充作底層語符列并作進一步轉換。指派給一個句子組構成分的一系列短語標記稱作轉換派生過程或轉換歷史。