A Cognitive Study On Semantic Extension Of English Spatial Prepositions

English is very rich in various senses of prepositions. There are close relations between the high rate of their use and their semantic extension. Traditional linguists have studied the extension but there are some limitations on their studies. They only study them from the inner language system itself. They are limited to cases where senses are either expanded or narrowed or something else. Lexicon is regarded as an arbitrary repository of unrelated lexemes. Under this theoretical frame, prepositional polysemy is reduced to homonymy. The close relationships among distinct senses of the same proposition are ignored,let alone exploring the way of how the senses relate each other. Therefore, their studies can't reveal the nature of semantic extension of prepositions.Since the 1970s, under the influence of prototype theory and conceptual metaphor, cognitive linguists have argued multiple senses of a word are treated as related with one another both experientially and cognitively. Therefore, they have taken up the challenge of the alleged arbitrariness of prepositional usage. The demonstration that prepositional usage is highly structured has one of the main accomplishments of the cognitive linguistics.In cognitive linguistics, the conceptual system that emerges from everyday human experience has been shown to be the basis of natural language semantics. Prototype theory is adopted in the categorization. Cognitive linguists also hold that the different senses of a polysemous lexical item are related in non-trivial ways. Spatial concepts are of great importance in human conceptual systems and in their experiencing the world. Experientialism, highlighting the vital importance of experience in the cognition of human and language, is their philosophical basis. Cognitive linguists emphasize meaning is embodied. The extension of abstract meaning of a preposition is based on the physical experience. They also emphasize meaning essentially involves an"imaginative"projection by using mechanisms of schematization, categorization, metaphor and metonymy. By these cognitive mechanisms based on the physical experience, their senses are extended. Most of the cognitive studies (Lakoff, 1987) show that the lexemes of prepositions constitute a highly motivated system. The process, which extends senses from a central prototype to form a radial category, is systematic and widespread.Image schema, a mental schema in our mind, is a simple structure that constantly recurs in our everyday bodily experience. Lakoff and Johnson (1987) have summarized some image schemas such as the ORIENTATIONAL Schema, the CENTRAL-PERIPHERY Schema, the CONTAINER Schema and so on. The basic schemas form the primary senses of the spatial prepositions. The image schema consists of TR, LM and PATH. When certain elements of the schema has been highlighted but not broken from the framework of the basic image schema, the transformations are born. The transformations cause other spatial senses, from which many metaphorical senses are extended by metaphorical mapping in different domains.Based on this research, this thesis explores the experiential basis of semantic extension of prepositions and the structure of extension. In spatial domain, the spatial senses of prepositions are extended. The metaphorical senses are extended from this spatial domain to the abstract domains. The thesis points out that metonymy is the cognitive mechanism of extension of spatial senses and metaphor is the important cognitive mechanism of metaphorical semantic extension. By analyzing, the conclusion is demonstrated reasonable. The last chapter is the case study of the preposition under. This chapter starts with the determination of primary sense of under. Then it focuses on how its spatial senses are extended from the central image schema to its transformations by metonymy. Next, this part also focuses on how its metaphorical senses are extended in terms of the central image schema and transformations by metaphor. In these analyses, this thesis summarizes four kinds of relations: the relation of UP-DOWN, the relation of HIGH-LOW, COVERING relation or the relation of IN-OUT and the relation of SOURCE-PATH-GOAL. Lots of metaphorical senses of under are derived from these basic spatial relations. In this thesis, the relations between the senses derived from central image schema and those derived from its transformations are explored at length. The relations between the spatial senses derived from central image schema and transformations and the metaphorical senses derived from them are also explored at length. The above analyses demonstrate that the sense extension of the spatial preposition is motivated by image schema, which also provides the root for metonymic and metaphorical extension. The semantic network of under is diagramed finally. By the examination of the semantic network of the preposition under, the characteristics of the semantic structure of prepositions have been demonstrated: the prototypical sense is in the central status in the semantic structure of a preposition; metonymy and transformations of image schemas are the important means to extend its spatial senses, and metaphor is the important means to extend its metaphorical senses; the distinct senses of a preposition are linked by family resemblances; all the senses are in different status in this structure.