UBC Theses and Dissertations
UBC Theses and Dissertations
Generative-transformational sketch of Portuguese syntax : a computer model Machado-Holsti, Mina Estrela
This dissertation presents a grammar for the description of the principal syntactic structures of Portuguese in the general linguistic framework of generative-transformational theory. The grammar is a device which defines the semantically interpretable deep structure and the graphemically interpretable surface structure for a set of Portuguese sentences. When a human being hears an utterance, he uses his knowledge to understand it. This requires not only grammar but also his knowledge of words, the context of the sentence, and most important, his knowledge of the subject matter. To write a computer program which understands natural language, we need to understand what language is and what it does. Language can be approached as a set of mathematical rules and symbols, or as a system intended to communicate ideas. Language can also be viewed as a process of transforming a structure of concepts in the mind of the speaker into a string of sounds or written symbols, and back into concepts in the mind of the hearer or reader. In order to talk about concepts we must understand the importance of mental models. There is, of course, no way of actually observing the internal workings of a person's mind. The process of understanding a sentence has to combine grammar and reasoning in a closely interrelated manner. A computer model is not a detailed psychological theory of how a person interprets a language, but the present study reveals that there may in fact be a high level of isomorphism between the theory of language, the computer grammar and the individual's language. The first part of this dissertation presents a review of the current state of linguistic theory and a practical application of transformational grammar as a methodological preliminary. This survey is necessary in order to explain the adoption of certain principles which will serve as a theoretical framework for my Portuguese grammar. The examination of this body of theory also justifies the adoption or rejection of certain principles that underlie my conception of a formalized model of linguistic description. In presenting a description of the formal model of a grammar and the generation of its syntactic structures I examine the properties of different generative-transformational systems. The formal model, based on many aspects of linguistic theory, is a priori but testable against empirical phenomena. It has the features of a metalinguistic representation of linguistic elements and classes, with a mathematical, logical and linguistic notational system of operators and operations. This generative-transformational model is non-exclusive in that its formal postulates and operations include Boolean classification, in the sense that its symbols are elective. The computer model consists of a grammar format and algorithm for deriving sentences. The features of the model and the system include a formal description of the syntax of transformational grammar, a phrase structure scheme, a format for the lexicon and lexical insertion algorithm, and a language for specifying the traffic rules of the grammar. The model presented in the thesis has been shown to have the capacity to generate grammatical sentences. It is also able to predict phenomena in non-deviant expressions and to ascribe to them a structural description. The formalization of the syntactic rules of this model has been tested and verified with the help of an adaptation of J. Friedman's computer program.
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