The language produced by learners learning a second language is extremely varied. It can range from one learner to another in regard to many factors. These variations can be accounted for by a number of ideas including: first language (L1) interface, age differences, motivation, self-confidence, aptitude, anxiety, gender and social distance. In this essay I will define SLA and then outline five of the main linguistic theories. These outlines will form the basis for my analysis of the differences in language that are produced by learners. Finally, I will consider what level of impact these theories have and how they can account for these differences and, the many difficulties and successes that learners have on their way to learning a second language. 2. What is SLA and what accounts for the language produced by learners? Saville-Troike (2006: 2) defines SLA as not just the learning of a subsequent language to that learnt in childhood but also the study of the processes involved and of those who are learning it. The language produced by learners changes as they learn the language and that language can differ from one student to another, even if they have the same L1. The following theories provide an insight into how and why this language may vary. Some are backed up by empirical data, others are not, but all have their strengths and weaknesses and they all have supporters and critics. 3. The main theories in SLA
3.1. Contrastive Analysis Hypothesis (CAH)
In terms of the principles of CAH, Gass and Selinker (1994: 59) state that it is "a way of comparing languages in order to determine potential errors for the ultimate purpose of isolating what needs to be learned and what does not need to be learned in a second language learning situation".Saville-Troike (2006: 34-35) explain that it focuses on the differences and similarities between the L1 and the Second Language (L2). This means that the similarities and differences between L1 and L2 play a crucial role in learners' production. Saville-Troike (2006: 35) also points out that there will be a transfer of elements acquired in the L1 to the target L2. This transfer is considered positive if the same structure exists in both languages and the transfer results in the correct production of language in the L2. However, it can also be negative if a language structure from the L1 does not exist in the L2 but the structure is transferred leading to the production of incorrect language. Arab students often omit the verb to be. For example, this book mine for this book is mine since both of them have the same meaning in Arabic /هذا الكتابُ لي /həðəlkɪtəbʊlɪ/. This kind of error might be made since the verb to be is rarely used in the present tense in Arabic. Because of this, Arab students may apply the Arabic rule to English. On the other hand, Arabic and English share the same idea regarding the position of object pronouns. The object pronouns are placed after the verb in English and Arabic. In contrast, with French, they occur before the verb. Mitchell and Myles (1998: 30) say that the predictions of CAH, that all the errors made in learning the L2 are due to interface from L1, were shown to be unfounded. They claim that many studies and research explain convincingly that the majority of errors could not be attributed to the L1. In other words, CAH might not predict learning difficulties, and was only useful in the retrospective explanation of errors. This point considerably weakened its appeal. However, the heightened interest in this area did lead to the origin of Error Analysis. 3.2. Error Analysis (EA) and Interlanguage (IL)
3.2.1 Error Analysis (EA)
Mitchell and Myles (2004: 29-30) consider this approach to be influenced by behaviorism through the use of fundamental distinctions between the learners' first and second languages to predict errors, adding that EA showed that CA was not able to predict...