Polysemy has more than one meaning. To some extent, this is due to the rhetorical device. Metonymy and Metaphor are common inrhetorical device.Specialization in asocial milieu is one of the reasons.

2.2 The main problem of polysemy in pratice

   In pratice, there are many problems of polysemy. In learning polysemy, the first proplem we are faced with is how to understand the meaning in this polysemy.

   Most of the learners can only remember one or two senses.They can not remember derivational meanings but primary meaning. Learners are not interested in derivational meanings and have not effective skill for polysemy.Chinese students’ poor methods of learning by rote made them unable to deal with the problems in his study of polysemy flexibly. Students don’t know the relation between two meanings.They can only learn polysemy by rote.

A large number of polysemy have’t regularity and uncontrollability,  for learners, It is very difficult to remember. Learners don’t know how to use polysemy. In specific language environment, learners don’t know which meaning they should use. Presently polysemy learning is a very big difficulty in vocabulary learning in English.

2.3 Introduction to Cognitive Semantics

Semantics examines how meaning is encoded in a language.It is not only concerend with meanings of words as lexical items, but also with levels of language below the word and above it, e. g. Meanings of morphemes and sentences. The following are what the key concepts look like: semantic components, denotation of words, sense relations between words such as antonymy and synonymy, sense relations between sentences such as entailment and presupposition and more.

Cognitive semantics is very important in researches of contemporary linguistics.Cognitive semantics is an effective approach to analyze the natural language that puts special emphasis on language as an instrument for organizing, processing and conveying information.Both cognitive semantics and conceptual semantics take psychologist linguistic view which stresses the study on mental processes and cognitive strategies.According to cognitive semantics, semantic extension is a process from the basic semantic meaning to other meanings through metaphor, metonymy or other cognitive means. Polysemy is one of the important research fields of cognitive lexical semantics, in which the linking mechanisms among the senes is considered as a very challenging one.

Chapter3 Cognitive Study of polysemy

3.1 Prototype Theory and polysemy

The prototype theory is a cognitive science theory developed by Eleanor Rosch in the early 1970s.In Rosch's theory,She found that each category is organized around a center, the prototype, which is described by means of properties that are characteristic, typical of the category members.Indeed, all objects in a category are not equivalent: some are better examples and more characteristic of the category than others. According to the prototype theory, certain features of a category have equal status, and thus, examples that represent all or most of those features become the prototype for that category. Items that do not share the majority of these features may still belong to that category, but do not represent the prototype Primarily, the prototype theory deals with how inpiduals categorize and stereotype certain items in language. Such understandings help psychologists understand and study the acquisition of vocabulary, inpidual mental lexicons, and the development of linguistic skills in inpiduals. Understanding how the mind categorizes and classifies information, as well as how that process is affected by cognitive development, culture, and early learning experiences, aids in helping students gain vocabulary and develop more advanced language skills.