二语习得往往建立在一语习得的基础之上,一语习得的经验以及一语的语言知识无疑将迁移于二语习得。一语与二语可能同属于同一个语系,也可能分别属于不同语系,不论如何,一语对二语的迁移作用是不可回避的,而语法则是实现这种迁移作用的重要因素。二语习得理论研究的是非母语习得的内在规律,探索如何利用已有的母语知识获得二语的交际能力。外语学习的研究在于揭示在特定的语言环境中如何掌握该门语言的规律。二语习得理论涵盖了包括外语学 Second language acquisition is often based on the acquisition of a language, the acquisition of a language experience and language knowledge of a language will undoubtedly migrate to second language acquisition. Language and language may both belong to the same language family, may also belong to different language families, no matter what, a language on the role of second language transfer can not be avoided, and grammar is an important factor in the realization of this role in the transfer. Second language acquisition theory is the study of the inherent laws of non-native language acquisition, explore how to use existing knowledge of mother tongue to obtain second language communicative competence. The study of foreign language learning lies in revealing how to grasp the law of the language in a specific language environment. Second language acquisition theory covers including foreign languages