Definition of Language（What is Language?) Based on Sapir， Hall Chomsky

It's a system of arbitrary vocal symbols used for human communication.

1  systematic 指语言的要素是按照规则组合在一起的。

2  arbitrary 语言符号是任意的，每一个语言象征和它所指的东西之间是没有什么规则可循的，而是约定俗称的。不同语言对同一种事物有不同的称呼，该物体时不变的，而这种称呼是任意的。“不管用什么称呼，玫瑰的香味永远是一样的。”-莎士比亚

3  vocal symbols  发声的语言系统，先有说，后有写。

4 human-specific 人类所特有的，与动物的语言是totally different.

简单地一句话概括了语言最基本的特征。

Design\defining features of human language

                      by Charles Hockett(American linguist)

1. Arbitrariness: 

No logical connection between meanings and sonds.( 只有少数一些不是完全任意如onomatopoeic words(拟声词）photo 和 copy是arbitrary，但是photocopy就不是完全任意的。有少数compound words(复合词)就不是完全任意的。)

意义：makes it possible to have an unlimited source of expressioms

2. Productivity/ Creativity

Peculiar to human languages, users of language can understand and produce sentences they have never heard before.(人可以说些他们从来没有听过也没有见过的话。如 A red-eyed elephant is dancing on the hotel bed. 我们仍然是可以理解的。)

animals`s calls are limited.

3. Displacement:

Language can be used to refer to things which are present or not present, real, imagined matters in the past, present or future, or in far-away places.(把语言用来指不是眼前的东西，过去的东西，将来的东西,不存在的想象的东西，在很远很远地方的东西。)

4. Cultural tramission:

 Language is culturally transmitted through teaching and learning, rather than by instinct.(语言文化的传递通过教与学。)

5.Duality: Lower level-sounds(meaningless);

         High level-meanging(large units of meaning0

Functions of language

1. Phatic function--establsihing an atmosphere or maintaining social contact

2.Directive function--get the hearer to do something

3.Informative function--give information about facts

4.Interrogative function--get information from others

5.Expressive function--express feelings and attitudes of the speaker

6.Evocative function--creat certain feelings in the hearer(amuse, startle, sooth, worry or please)

7.Performative function--language is used to do things to perform actions