Abstract The age factor has been the focus of linguists in the field of Second Language Acquisition (SLA) research. This paper introduces the current situation of the research of age and second language acquisition from the concept of Critical Period Hypothesis, the viewpoints of its supporters and opposers，and universal grammar, and analyzes characteristics of children and adults second language acquisition , and compares proficiency of second language acquisition between children and adults separately from the pronunciation acquisition, grammar acquisition, morphology and syntax acquisition, then discuss the reasons of age influence on second language acquisition from three aspects of the physiology, cognition and emotion. Finally, combined with the actual situation of language acquisition, some inspirations are given according to second language learning of the Chinese people, so that they have a deeper understanding of second language acquisition, and grasp second language better. 59101

Key words: age; second language acquisition (SLA); optimal age; cognition

摘要年龄因素一直是二语习得研究领域语言学家们关注的焦点。本文首先从关键期假说的概念，关键期理论支持派的观点和反对派的理由和普遍语法等两个方面对年龄与二语习得研究的现状进行了介绍，并分别对儿童与成人二语习得的特点进行了分析，而且又分别从语音习得，语法习得，词法和句法习得三个方面对儿童与成人在二语习得效果的优劣进行了比较.最后结合实际情况，针对我国学习第二语言的人们，给他们一些启示，使他们对二语习得有更深的了解，更好的掌握第二语言。

毕业论文关键词：年龄因素；二语习得; 最佳年龄；认知

Contents

1. Introduction 1

2. Literature Review 1

2.1 The Concept of Critical Period Hypothesis 2

2.2 The Supporters and Researches of Critical Period Theory 3

2.3 The opposers and Researches of Critical Period Theory 4

3. The Characteristics of Young Age 5

3.1 From the Perspective of Critical Period 5

3.2 From the Perspective of Foreign Language Attrition 7

4. Characteristics of the Older Age 8

4.1 From the Perspective of Cognition 8

4.2 From the Perspective of Learning Rate 9

4.3 From the Perspective of Learning Motivation 10

5. Analytical Comparison between Children and Adult in Second Language Acquisition 10

5.1 Analysis from the Perspective of Speech Acquisition 10

5.2 Analysis from the Perspective of Grammar Acquisition 11

5.3 Analysis from the Perspective of Lexical and Syntactic Acquisition 12

6. Conclusions and Recommendations 12

6.1 The Initial Age of Second Language Acquisition 12

6.2 Implications for Second Language Acquisition 13

Works Cited 14

  1. Introduction 

The influence of age on the second language acquisition has been discussed since 1960s.Age factor has been showed by many research results that it is one of the most important factors in the second language acquisition, but some scholars believe that there is no inevitable connection between age and second language acquisition. In our country, not only scholars do some research on the impact of age in the process of foreign language learning, but also lots of teachers and parents are concerned, a great number of them think that children learn a foreign language better than adults. Because of this, learning foreign language in a younger age has become a common phenomenon. Though researchers have no agreeable conclusion, the gap is obvious in different age groups. So we should first find out the same points and differences between different age groups, and find out the best learning age. We can find differences by comparing and determine its existing causes. Finally, we can find appropriate solutions to make learning easier and more relaxed, and let learn second language acquisition faster.