【Abstract】Both first language acquisition and second language acquisition are the base of studying language teaching and learning. Discuss on similarities and differences between them from linguistic， cognitive and social perspectives gives a better understanding of first and second language acquisition. This essay illustrates the similarities and differences and discuss their pedagogical significance on the basis of teachers understanding and experience.

【Key words】first language acquisition； second language acquisition； similarities； differences

First language acquisition （FLA）， literally， is relevant to the acquisition of the mother tongue （Ellis， 1997）. SLA， short for Second language acquisition， refers to the study of the acquisition of the additional language subsequent to learning the mother tongue in different circumstances （Ellis， 1997）. Having been researched for over 40 years by many cross-disciplinary scholars such as Chomsky and Krashen， the study of FLA and SLA contributes to pedagogical development considerably. To make a comparison and contrast between FLA and SLA， a clear picture of both studies which will help in improving pedagogy prospect can be drawn. This essay will illustrate the similarities and differences between FLA and SLA from linguistic， cognitive and social perspectives and discuss their pedagogical significance on the basis of teachers understanding and experience.

From the linguistic perspective， the expected leaning stages and the linguistic competence in the final state are comparable between FLA and SLA. As Saville-Troike （2006） writes， for each of the L1 and L2 learner， the language of lexicon， phonology， morphology， syntax and discourse is expected to be applied essentially. Whereas， there is a big difference in linguistic competence， which is defined as the outcome of language learning achieved by L1 and L2 learners in real situation. According to Saville-Troike （2006）， the L1 learners can obtain the underlying knowledge of the mother tongue unconsciously with no difficulties. Some believe that Universal Grammar， which is proposed by Chomsky， facilitates the mastery of the underlying knowledge of the mother tongue （Mitchell and Myles， 2004）. Conversely， Saville-Troike also points out that L2 learners seldom reach the high level of competence on account of the fossilization in certain level. In the process of acquiring the second language， learners seem to make the same mistakes repeatedly or have a certain accent （Littlewood， 1991）. In general， fossilization is an inevitable phenomenon during the process of L2 acquisition no matter how much effort have been made for most of the learners. From pedagogical perspective， teachers can help students get over the fossilization by giving corrective feedback when some mistakes are made continually based on the analysis of the students different learning features and the variety types of fossilization. Overall， analysed from the linguistic aspects， the most similar feature is the necessity of the same linguistic stages for FLA and SLA and the linguistic competence differs between L1 and L2 learners.

Psychologically， similarities and differences can be found in terms of the acquiring period and cognitive factors between FLA and SLA. Firstly， one assumption named Critical Period Hypothesis is made to generalize that over a certain age， the ability of learning a language seems to be limited （Saville-Troike， 2006）. Besides， Saville-Troike also indicates that Chomsky proposed a hypothesis that there is a Language Acquisition Device （LAD） in human beings brain. As she demonstrates， the LAD maintains the acquisition of languages no matter it is L1 or L2. Despite lack of evidence and being criticised by other scholars， both hypothesises still make a great influence on the study of FLA and SLA. As to the difference， the motivations vary between L1 and L2 learners. L1 learners， mostly children， are exposed to a setting surrounded by full of L1 speakers. These children study the mother tongue because of the urgent need of communicating with people around （Saville-Troike， 2006）. The motivations of L2 learners are far more complicated. Ellis （1997， 75） summarizes the motivations into 4 categories – ‘instrumental， integrative， resultative and intrinsic. In reality， a great portion of Chinese students learn English due to instrumental motivation， which means their objectives are to pass the examination or find a good job. Fewer students are motivated by interest on English. These facts lead to the grammatical competence but unsuccessful language acquisition. On possible solution is that teachers generate the integrative motivation of students and stimulate their desire for learning. In brief， Critical Period Hypothesis applies to both FLA and SLA； Also， cognitive factors such as motivations differ between L1 and L2 learners.

Interaction is considered as the basic and common requirement for both FLA and SLA， and the circumstance of learning is a distinct difference between them. With regard to interaction， it is essential for learners to achieve an advanced language proficiency （Saville-Troike， 2006）. L1 and L2 learners interact under different circumstances. Ellis （1994） claims that mother tongue is acquired in the social context such as home， while SLA generally happens under 2 circumstances – natural and educational settings. To be more precise， natural setting refers to home， workplace and so on and educational setting， namely， is being educated in the classroom or under standard instruction. Individually， the time of exposure to the L1 is far more than L2. Learning English as a subject does not make sufficient time and excise for students. Therefore， under the educational environment， teachers can create a L2 learning setting and more opportunities to speak L2. In addition， the new learning setting may increase the interaction between students， and even stimulate their interest and motivation for SLA. Furthermore， the conversation between teachers and students is also interaction. In china， students always wait for instructions of learning from teachers because of the distance between them. In that case， teachers should make more efforts to shorten the distance and make them more active. Thus it may be possible that the situation of lack of exposure to L2 can be changed.

All in all， the similarities between FLA and SLA are reflected in 3 aspects， linguistic language of the stages， acquiring period and the necessity of interaction. The differences are analysed from linguistic competence， learning motivation and language learning contexts. Through the analysis of the comparison and contrast， a considerable significance can be attached to the pedagogical improvement. Combined with the real situation and practical experience， teaching a second language should take the language setting， leaners different learning strategies and factors into consideration. Besides， L2 learners may improve the proficiency through adopting some useful regulations and theories in FLA. There are still numerous unknown fields in the study of FLA and SLA need to be explored. It is believed that a great significance will be carried out to the pedagogical implication through the exploration.

References：

[1]Ellis，R.（1994）.The study of second language acquisition.Oxford：Oxford University Press.

[2]Ellis，R.（1997）.Second Language Acquisition.Oxford：Oxford University Press.

[3]Littlewood，W.（1991）Foreign and second language learning： language acquisition research and its implications for the classroom.Cambridge：Cambridge University Press.

[4]Mitchell，R.and Myles，F(xiàn).（2004）Second language learning theories，2nd edn.London：Arnold Publishers.

[5]Saville-Troike，M.（2006）Introducing Second Language Acquisition.Cambridge：Cambridge University Press.

作者簡介：趙蘭（1989-），女，貴州遵義人，碩士研究生，遵義醫(yī)學(xué)院外國語學(xué)院助教，主要研究二語習(xí)得、外語測試、英語教學(xué)。