1.2 Language environment and the Critical Period Hypothesis语言环境和临界期假说

1.      The environment: (behaviorist, innatist, interactionist)

In behaviorist approach, language environment plays a major role in providing both language models to be imitated and the necessary feedbacks among which the positive reinforcement or reward encourages children’s efforts and facilitates the “correct” learning of the language while the negative feedback discourages children to repeat the “mistakes”.在行为主义者理论中，语言环境在提供被模仿的语言模式和必要的反馈中引起到了主要作用。在反馈中，积极的强化或奖励能鼓励儿童作出努力，并促进他们“正确的“学习语言。而负面的反馈使儿童失去再去犯“错误”的勇气。

Innatist view emphasizes more on children’s internal processing of the language items to be learnt. The environment functions as a stimulus that triggers and activates the pre-equipment UG to process the materials provided by the linguistic environment around the children. The interactionist view calls for the quality of the language samples available in the linguistic environment, only when the language is modified and adjusted to the level of children’s comprehension, do they process and internalize the language items.语法天生主义者观更强调儿童对于要学的语言项的内在处理。环境的功能起刺激作用，它出发和即或先天具备的ＵG来处理由儿童周围的语言环境所提供的材料。互动主义者观讲求语言环境中语言样本的质量，只有将语言限定或调整到儿童可以理解的水平时，他们才能处理语言项目，并将其内在化。

2.      The age

(this factor can be used to explain why the teenagers could learn foreign language efficiently and effectively.这个因素可以用来解释为什么少年学习语言既有效率又有效)

Critical Period Hypothesis:临界假说 the theory that in child development there is a period during which language can be acquired more easily than at any other time. According to the biologist Lenneberg, the critical period lasts until puberty (around age 12 or 13 years), and is due to biological development. Lenneberg suggested that language learning may be more difficult after puberty because the brain lacks the ability for adaptation. This, he believed, was because the language functions of the brain have already been established in a particular part of the brain; that is, because lateralization 偏侧优势(see Brain) has already occurred by this time.认为儿童发展时期内有一段时间语言习得最顺利的一种理论。根据生物学家Lenneberg，关键时期持续至青春期（约十二或十三），这是处于生物发展原因。他还提出，语言过了青春期，由于大脑缺乏适应能力，会变得越来越难。他认为，这是因为大脑的语言功能已经在大脑某一部位确立，也就是因为这个时期偏侧优势已经出现了。

Lateralization: the development of control over different functions in different parts of the brain is known as cerebral dominance or lateralization.大脑各部分对不同功能的控制称为脑单侧偏利或偏侧优势。

管辖语言的一般在左脑，这区域损伤会引起失语症；另一区域，人们认为它与理解语言有密切地联系。

1.1  Stages in child language development 儿童语言发展的阶段

The following will outline some main stages of children’s language development如下列出儿童语言发展的几个主要阶段

1.1.1        Phonological development语音的发展

1.1.2    Vocabulary development词汇的发展

1.      Under-extension：外延缩小

2.   Over-extension 过分延伸

Prototype:典型/原型 a person or object which is considered (by many people) to be typical of its class or group.指被（多数人）认为是某一类或一组的典型的人或物