Michael Long (1985，1996) 以Krashen的理论为基础，推出互动假说。互动假说强调L2的学习应该发生在自然的环境中，在此环境中学习者和说母语的人(NS)，或语言能力很好的L2使用者互动。他聚焦于这种互动的本质，认为这本质能帮助L2的学习过程。
Long (Ellis, 1997:p.47, Lightbrown & Spada, 1999:pp.42-44; 引自Oberli, 2003) 假定互动对语言学习的影响来自对话中的意义协商 (negotiation of meaning)。他认为澄清 (clarification) 或改变说话的方式（称为修正后的输入，modified input）等思考及自我改正的过程能提供语言学习者可理解的输入，而此种输入是修正过的互动 (modified interaction) 的结果。如果这种意义协商发生于语言能力更精熟的说话者，相信学习者将贴近最佳发展区 (ZPD) 而有更上一层楼的表现。所以他提倡老师和学习者之间的口语修正 (conversational modification)让传递的信息更容易理解，因此能减少语言习得的困难 (Long, 1996)。
根据Long的观点，互动 (interaction) 与输入(input)是语言习得过程中两大角色，而对话及其它互动沟通发展是语言规则的基石。至今已有大量的研究报告支持互动与语言习得之间的相关性 (Swain & Lapkin, 1998; Gass, Mackey, & Pica, 1998；Van Lier, 1996；Jordens 1996；Loschky, 1994; Gass & Varonis, 1994; Pica, 1987; 引自Brown, 2000)，如同Van Lier (1996: p.188)所说的：学习者乃经由社会协调互动中建构新的语言。more
Hatch (1978) and by Long (1981, 1996) consider that input alone is not sufficient to explain SLA. Hatch disagrees that learners first learn structures and then use them in discourse. She considers the reverse possibility. ―One learns how to do conversation, one learns how to interact verbally, and out of this interaction syntactic structures are developed (p. 404)‖.
Based on an empirical study, Long (1981) observed that in conversations between native and non-native speakers, there are more modifications in interaction than in the input provided by the native speakers. He does not reject the positive role of modified input, but claims that modifications in interactions are consistently found in successful SLA. Long (1996:451-2) suggests that
negotiation for meaning, especially negotiation work that triggers interactional adjustments by the NS(Native Speakers) or more competent interlocutor, facilitates acquisition because it connects input, internal learner capacities, particularly selective attention, and output in productive ways.
Larsen-Freeman and Long (1991:266) argue that the interactionist views are more powerful than other theories ―because they invoke both innate and environmental factors to explain language learning‖. I would add that they are the first to view language not only as a matter of syntactic structures but also as a matter of discourse. Regarding investigation, the interactionist research uses data recorded from free conversation or controlled
conversation tasks.
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二语习得研究方法35年回顾与思考－－文秋芳
二语习得研究的九大主流理论和研究走向— 《二语习得理论》介绍
http://sla.sjtu.edu.cn/thesis/二语习得研究的九大主流理论和研究走向_二语习得理论_介绍.pdf
国内外二语习得研究对比
http://www.mianfeilunwen.com/Yingyu/Xiangguan/30940.html
Swain 输出假说理论
自从 Krashen 提出了输入假设理论以来，在语言教学和研究过程中， 人们对语言输出的作用一直不是很重视，相应的研究也较少。多项研究表明，仅靠 Krashen 的输入假设理论中提到的“可理解输入”对外语学习者提高外语水平是不够的。Swain 曾对语言学习者进行过大量的调查，结果发现， 学习者如果想使他们的外语既流利又准确的话，既要接触大量的“可理解输入”，又要产出“可理解输出”。 输出在语言学习中具有重要作用，除了可以
提高学习者外语的流利程度外， 还可以提高学习者的准确性。［1］Swain 指出，“熟能生巧 ”（practice makes per－fect ），大量的语言“输出”性实践，起到了“反复操练 ” 的作用，从而提高了语言的流畅性。Swain（1985 ）认为，“除了必要的可理解性输入外，学习者必须有机会使用所学语言， 这样才有可能达到流利、类似母语者的水平 。 ［2］ 另 一 方 面 ，大 量 语 言“输出” 实践帮助学习者逐步提高语言的准确性，这是因为：首先，输出可以促进学习者对目标语的有意注意。也就是说，在产 生 目 标 语 时 ，学 习 者 可能会注意到他们想说的与他们能说的之间存在着差距， 这促使他们发现他们有哪些地方不懂或一知半解。其次，输出是检测理解能力和语言组织是否良好的方法。通过“输出”性语言实践，学习者检验了自身表达是否可被理解， 以及所用语言形式和结构是否正确、得体。再 者 ，学 习 者 的 输 出 有着元语言（metalinguistic ）的功能，使得他们能够控制并内化语言知识。 因此，Swain 提出了语言输出假设（Output Hypothesis ）理论，认为语言输出有以下几个功能和作用： ［3］
（ 一） 注意 / 触发功能（the noticing /triggeringfunction 或 consciousness raising function ）。 输出会刺激注意，即学习者在产出目标语时，他们既要注意语言形式又要注意语言结构， 于是他们会发现自己想要表达的 与 实 际 的 表 达 之 间 存 在 着 差 距 ，这种差距会使他们意识到自己不懂或半懂的语言知识， 进而可以触发对现有语言知识的巩固或获得新的语言知识的认知过程。
（ 二 ） 验 证 假 设 功 能 （hypothesis testing ）。语言学习被认为是一
个对目标语进行不断的假设并验证和修改的过程。 学习者可以把语言输出视为验证自己在学习过程中形成的有关语言形式和语言结构新假设的途径。“互动和反馈”是验证假设的前提，学习者可以通过对方的反馈来检验自己所产出的目标语的准确性，进而尝试新的语言形式和结构，使自己的语言使用更为准确。 （ 三） 元语言功能（the metalinguistic function /conscious reflection ）。Swain 认为，当 学 习 者 对 自 己的目标语用法进行反思时，输出起着元语言功能，输出能够控制和内化他们的语言知识。 学习者通过分析和反思可以得到与语言的形式、 结构等相关方面知识的雏形。（ 四） 促成自动化（developing automaticity ）。输出能激发学习者从以语义为基础的认知处理转向以句法为基础的认知处理， 在句法和语法习得中具有潜在的重要性。
由此可见，输入 虽 然 重 要 ，但 如 果 没 有 输 出 ，输入永远只能是语言知识储存于学习者的大脑中，而不会转化为语言技能。 More 输出假设理论：历史与未来—Merrill Swain教授专访
Swain (1985, 1995) also goes against Krashen‘s radical position towards the role of input and argues in favour of the output hypothesis. She claims that practicing the language helps learners observe their own production, which is essential to SLA. It is her contention that ―output may stimulate learners to move from the semantic, open-ended non-deterministic, strategic processing prevalent in comprehension to the complete grammatical processing needed for accurate production‖ (Swain,1995: 128). She explains that ―learners may notice a gap between what they want to say and what they can say, leading them to recognize what they do not know, or know only partially‖ (p. 126). She highlights that ?noticing‘ is essential to SLA and also hypothesizes that output has other two functions: to test hypothesis and to trigger reflection, a metalinguistic function. She explains that learners ?may output just to see what works and what does not‖ (p. 132) and that they reflect upon the language they produce when negotiating meaning because the content of negotiation is the relation between the meaning they are trying to express and the language form.
As far as research is concerned, the investigations in this perspective have mainly used experiments with control groups, pre-tests and post-tests. Think-aloud protocol was also used in Swain and Lapkin (1995) to see the impact of output upon the learners' thought processes. More
Vygostky: Socio-cultural perspectives
Vygostky（1896～1934）前苏联心理学家。与皮亚杰是同时期的人物。但不同于皮亚杰认知发展泛宇宙统一的观点，维考斯基的理论强调文化、社会对儿童认知发展的影响。 社会文化发展理论起源于心理的文化—历史观，其基本观
点是：
人们所处的环境与人们的内部心理有着密切的联系，人们所处的环境充斥着先辈们的文化以及与此相关的物化成果。此理论强调人本质上是社会的，认为人类的智能来自于我们所处的社会或文化环境。针对语言学习来讲，社会文化发展的观点认为单纯的语言输入并不保证语言习得的发生，主张结合语言学习过程中的情境、行为、动机等因素来看待语言学习。
在维果茨基的社会文化发展理论中，活动（Activity） 、调节（或称中介）（Mediation） 、内在/自我话语（Inner/Private Speech） 、最近发展区（Zone of Proximal Development）是四个非常重要的概念。这四个概念相互联系、紧密结合，构成了一套完整的从社会文化角度考虑关于教育研究及教学实践的思想体系。很多西方学者称之为“社会性建构” （Social Constructivism）思想。 “最近发展区”（ZPD）--维果茨基认为，儿童的发展水平有两个层面，即事实性发展水平（actual level）与潜在性发展水平（potential level） 。事实性发展水平指的是那些已经稳固确立的、能独立地解决处理问题的能力，而潜在性发展水平则是在特定条件下儿童还未完全形成的、但可以在他人帮助下完成任务的能力。两个水平之间的距离便是所谓的最近发展区（Vygotsky，1978） 。 More: 社会文化发展理论指导下的二语习得研究及教学 第二语言习得的互动博弈假说——二语习得理论的哲学思考
Vygotsky’s sociocultural theory
Vygotsky‘s sociocultural theory of human learning describes learning as a social process and the origination of human intelligence in society or culture. The major theme of Vygotsky‘s theoretical framework is that social interaction plays a fundamental role in the development of cognition. Vygotsky believed everything is learned on two levels.
First, through interaction with others, and then integrated into the individual‘s mental structure.
Every function in the child’s cultural development appears twice: first, on the social level, and later, on the individual level; first, between people (interpsychological) and then inside the child (intrapsychological). This applies equally to voluntary attention, to logical memory, and to the formation of concepts. All the higher functions originate as actual relationships between individuals. (Vygotsky, 1978, p.57)
A second aspect of Vygotsky‘s theory is the idea that the potential for cognitive development is limited to a \of proximal development\the student is cognitively prepared, but requires help and social interaction to fully develop (Briner, 1999). A teacher or more experienced peer is able to provide the learner with \support the student‘s evolving understanding of knowledge domains or development of complex skills. Collaborative learning, discourse,
modelling, and scaffolding are strategies for supporting the intellectual knowledge and skills of learners and facilitating intentional learning.
“the distance between the actual developmental level as determined by independent problem solving and the level of potential development as determined through problem solving under adult guidance, or in collaboration with more capable peers.‖（ L.S. Vygotsky: Mind in Society: Development of Higher Psychological Processes, p. 86）
Sociocultural theory
The sociocultural theory (SCT), based on Vygotskian thoughts, claims that language learning is a socially mediated process. Mediation is a fundamental principle and language is a cultural artefact假象 that mediates social and psychological activities. ―From a social-cultural perspective, children‘s early language learning arises from processes of meaning-making in collaborative activity with other members of a given culture‖ (Mitchell and Myles, 2004:200). Lantolf and Thorne (2007) defend that the principles of the SCT can also apply to SLA. They explain that ―SCT is grounded in a perspective that does not separate the individual from the social and in fact argues that the individual emerges from social interaction and as such is always fundamentally a social being‖ (p. 217-8). It is in the social world that the language learners observe others using language and imitate them. It is also with the collaboration of other