Language acquisition: refers to the child’s acquisition of his mother tongue, i.e. how the child comes to understand and speak the language of its community.语言习得是指儿童对其母语的习得，也就是儿童是如何逐渐理解和说其社区的语言的。

1.1  Theories of Child Language Acquisition儿童语言习得的理论

1.1.1        A behaviorist view of language acquisition行为主义者的语言习得观

That is the behaviorism: they believe that language learning is simply a matter of imitation and habit formation. 相信语言学习仅仅只是一个模仿和习惯形成的问题。

Disadvantages: 1. They imitate words selectively and according to their own understandings of the  sounds or patterns.他们有选择性地模仿，并且是根据他们自己的理解来模仿。

             2. What they imitate must be based on what the children have already known instead of what is “available” in the environment.他们模仿的东西必须基于他们已经知道的，而不是环境中“现有”的。（也就是根据他们已有的知识，以他们自己的方式对新鲜事物接受，然后才经过长时间整理，才可以形成正式符合规则的语言。）

1.1.1        An innatist view of language acquisition语法天生主义者的语言习得观

The language develops in the child just as other biological functions such as walking.人天生就具有语言能力，而且语言发展是和儿童的其他生物功能的发展一样，如行走。

Language acquisition device: LAD 语言习得机制 the capacity to acquire one’s First language, when this capacity is pictured as a sort of mechanism or apparatus.一个人获得第一语言的能力，这一机制被当作一种机能或器官时（的一种说法）。

In the 1960s and 1970s Chomsky and others claimed that every normal human being was born with and LAD (see Innatist hypothesis). The LAD included basic knowledge about the nature and structure of human language. 二十世纪六十和七十年代Chomsky及其他学者认为每一个正常的人 生来就有一个语言习得的机制。语言习得机智包括人类语言本质及结构的基本知识。

Universal Grammar: 普遍语法：a theory which claims to account for the grammatical competence of every adult no matter what language he or she speaks. 这理论认为，不管操什么语言，每个成人的语法都可用这种理论来描述。

It claims that every speaker knows a set of principles which apply to all languages and also a set of Parameters that can vary from one language to another, but only within certain limits.它认为每个说话者都掌握一套原理（principles）和参量，这些原理适用于所有语言，而参量则因语言而异，但这种差异是有一定限度的。

First language acquisition:第一语言习得 the learning and development of a person’s native language. Interest in the processes by which children learn their first language was prompted by the work of Chomsky, who argued that 一个人母语的学习及发展。Chomsky的研究引起了对儿童学习第一语言的过程的兴趣，他认为：

1.      children are born with special language learning abilities.儿童生来就有特别的语言学习能力。

2.      they do not have to be taught language or corrected for their mistakes不一定要教他们语言或纠正他们的错误。

3.      they learn language by being exposed to it.他们通过与语言接触而进行学习

4.      linguistic rules develop unconsciously.语言规则的发展在无意识中进行。