1.Semantics: the study of meaning2.Synonymy: the sameness or close similarity of meaning.3.Polysemy: while different words may have the same or similar meaning, the same one word may have more than one meaning4.Homonymy: the phenomenon thea words having different meanings have same form, i.e.,different words are identical in sound or spelling, or in both5.Hyponymy: the sense relation between a more general, more inclusive word and a more specific word6.Antonymy: words that are opposite in meaning7.Pragmatics: it is the study of how speakers of a language ues sentences to effect successful communication8.Speech act theory: it is a philosopher explanation of the nature of linguistic communicatin. It is aim to answer the question “what do we do when suing lanfuage?”9.Constatives: either state or discribe, and were thus verifiable10. Performatives: did not state a face or describe a state, and were not verifiable11.Locutionary act: It is the act of utterance words,phrases,clauses. It is the act of conveying literal meaning by means of syntax, lexion and phonology.12.Illocutionary act: It is the act expressing the speaker’s intention; It is the act performed in saying something.13.Perlocutionary act: It is the act performed by or resulting from saying something: it is the consequence of, or the change brought about by the utterance; it is the act performed by saying something14.cooperative principle: in making conversation, the participants must first of all be willing to coopreate; otherwise, it would not be possible for them to carry on the talk15.historical linguistics:it is the subfield of linguistics that studies language change.16.blending: a way of forming a new word by combining parts of two other words17.semantic broadening:the process in which the meaning of a word becomes general or inclusive than its historically earlier meaning18.protolanguage: the original form of a language family which has ceased to existnguage family: a group of historically relate laguages that have developed from a common ancestral language20.socilinguistics: the subdiscipling of linguistics thet studies language variation and language ues in social contexts21.speech community: a group of people who form a community andshare at least one speech variety as well as similar linguistic norms22.lingua franca: a variety of language that serves as a sommon speech for social contact among groups of people who speak different native languages or dialects23.pidign:a marginal contact language with a limited vocabulary and reduced grammatical structures, used by native speakers of other languages as a means of business communication24.diglossia: a sociolinguistic situation in which two very different varieries of languag co-exist in a speech community, each serving a particular social function and used for a particular situation25.euphemism:a word or expression that is thought to be mild, indirect, or less offensive and used as a polite substitute for the supposedly harsh and unpleasant word or expression26.psycholinguistics: the study of language in relation to the mind, with focus on the processes of language production, comprehension and acquisition27.cerebral cortex: the outside surface of the brain which receives messages from all the sensory oragns and where human cognitive abilities reside28.brain lateralization: The localization of cognitive of cognitive and percpetual functions in a particular hemisphere of the brain29.linguistic lateralization: hemispheric specialization or dominance forlanguage30.the critieal period: an early period of one’s life extending to the age of puberty, during which the human brain is most ready to acquire language naturally and effortlessly, a period that coincides with the period of brain lateralization for language functions31.caretaker speech: simple, modified speech used by parents, baby-sitter, etc.when they talk to young children who are acquiring their native languagenguage transfer:the effect of one’s first language knowledge on the learning of a second language33.interlanguage:the aproximate language system that a second language learner constructs which represents his or her transitional competence in the target language34.acculturation: a process of adapting to the culture and value system of the second language communnity。