Second language acquisition by David Nunan

MA English Sem.3, ELT1; Unit 2Department of English,

Maharaja Krishnakumarsinhji Bhavnagar University

Introduction• The term second language acquisition (SLA) refers to the

processes through which someone acquires one or more second or foreign languages. SLA researchers look at acquisition innaturalistic contexts (where learners pick up the language informally through interacting in the language) and in classroom settings. Researchers are interested in both product (the language used by learners at different stages in the acquisition process) and process (the mental process and environmental factors that influence the acquisition process). In this chapter I trace the development of SLA from its origins in contrastive analysis. This is followed by a selective review of research, focusing on product-oriented studies of stages that learners pass through as they acquire another language, as well as investigations into the processes underlying acquisition. The practical implications of research are then discussed, followed by a review of current and future trends and directions.

Background• The discipline now known as SLA emerged from comparative

studies of similarities and differences between languages. These studies were conducted in the belief that a learner's first language (LI) has an important influence on the acquisition of a second (L2), resulting in the 'contrastive analysis' (CA) hypothesis. Proponents of contrastive analysis argued that where LI and L2 rules are in conflict, errors are likely to occur which are the result of 'interference' between LI and L2. For example, the hypothesis predicted that Spanish LI learners would tend, when learning English, to place the adjective after the noun as is done in Spanish, rather than before it.

• Such an error can be explained as 'negative transfer' of the LI rule to the L2. When the rules are similar for both languages, 'positive transfer' would occur, and language learning would be facilitated. Where a target language feature does not exist in the LI, learning would also be impeded.

• Thus, English LI learners will encounter difficulty trying to master the use of nominal classifiers in certain Asian languages such as Cantonese, because these do not exist in English. In terms of pedagogy, contrastivists held that learners' difficulties in learning an L2 could be predicted on the basis of a systematic comparison of the two languages, and that learners from different first language backgrounds would experience different difficulties when attempting to learn a common L2.

• The CA hypothesis was in harmony with the prevailing psychological theory of the time: behaviourism. Behaviourists believed that learning was a process of habit formation. Linguistic habits acquired by individuals as their LI emerged would have a marked influence on their L2 acquisition. It is no coincidence that research questioning the contrastivist position emerged at about the same time as cognitive psychologists began to challenge behaviourism. A major shift in perspective occurred in the 1960s, when linguists and language educators turned their attention from the CA of languages and began studying the specific language learners used as they attempted to communicate in the target language. In an important publication, Corder (1967) made a strong case for the investigation of learners' errors as a way of obtaining insights into the processes and strategies underlying SLA. Errors were seen not as evidence of pathology on the part of learners (as suggested by behaviourism), but as a normal and healthy part of the learning process.

• The systematic study of learners' errors revealed interesting insights into SLA process. First, learners made errors that were not predicted by the CA hypothesis. Second, the errors that learners made were systematic, rather than random. Third, learners appeared to move through a series of stages as they developed competence in the target language. These successive stages were characterised by particular types of error, and each stage could be seen as a kind of interlanguage or 'interim language' in its own right (Selinker 1972).

• Not surprisingly, the field of SLA has been strongly influenced by LI acquisition. SLA researchers have looked to LI acquisition for insights into ways of investigating the acquisition process as well as the outcomes of the research. Particularly influential was a pioneering study by Brown (1973), who conducted a longitudinal case study of three children acquiring English as an LI. Brown traced the development of 14 grammatical structures, discovering that, contrary to expectations, there was no relationship between the order in which items were acquired and the frequency with which they were used by the parents.

Research• PRODUCT-ORIENTED RESEARCH During the early 1970s a

series of empirical investigations into learner language were carried out which became known as the 'morpheme order' studies. Their principal aim was to determine whether there is a 'natural' sequence in the order in which L2 learners acquire the grammar of the target language. Dulay and Burt (1973, 1974) - the principal architects of the morpheme order studies - found that, like their LI counterparts, children acquiring an L2 appeared to follow a predetermined order which could not be accounted for in terms of the frequency with which learners heard the language items. Moreover, children from very different LI backgrounds (Spanish and Chinese) acquired a number of morphemes in virtually the same order. However, the order differed from that of the LI learners investigated by Brown. A replication of the studies with adult learners produced strikingly similar results to those with children (Bailey et al. 1974).

• As a result of these and other investigations, it was concluded that in neither child nor adult L2 performance could the majority of errors be attributed to the learners' Lls, and that learners in fact made many errors in areas of grammar that are comparable in both the LI and L2, errors which the CA hypothesis predicted would not occur. Dulay and Burt (1974) therefore rejected the hypothesis, proposing instead a hypothesis entitled 'L2 acquisition equals LI acquisition' and indicating that the two hypotheses predict the appearance of different types of errors ('goofs') in L2 learners' speech.

• Briefly the CA hypothesis states that while the child is learning an L2, he [or she] will tend to use his native language structures in his L2 speech, and where structures in his LI and his L2 differ he will goof. For example, in Spanish, subjects are often dropped, so Spanish children learning English should tend to say Wants Miss Jones for He wants Miss Jones.

• The 'L2 acquisition equals LI acquisition' hypothesis holds that children actively organize the L2 speech that they hear and make generalizations about its structure as children learning their LI do. Therefore the goofs expected in any particular L2 production would be similar to those made by children learning the same language as their LI. For example Jose want Miss Jones would be expected since LI acquisition studies have shown that children generally omit functors, in this case the -s inflection for third person singular present indicative. (Dulay and Burt 1974: 96)

• The morpheme order studies indicated a predetermined order of acquisition for certain grammatical morphemes. Subsequent research also showed that this order could not be changed by instruction. However, the researchers were unable to explain why certain items were acquired before others. During the 1980s, however, a number of researchers studying the acquisition of German and English proposed an interested explanation for the disparity between instruction and acquisition based on speech-processing constraints (Pienemann 1989). They argued that grammatical items can be sequenced into a series of stages, each more complex than the last. However, this complexity is determined by the demands made on short-term memory, rather than by the conceptual complexity of the items in question. Take, e.g., third person -s, which morpheme studies had shown is acquired late. These researchers could explain why this was so. According to pedagogical grammars, the item is relatively straightforward. If the subject of a sentence is singular, add -s to the main verb.

• In the 1980s Stephen Krashen was the best-known figure in the SLA field. He formulated a controversial hypothesis to explain the disparity between the order in which grammatical items were taught and the order in which they were acquired, arguing that there are two mental processes operating in SLA: conscious learning and subconscious acquisition. Conscious learning focuses on grammatical rules, enabling the learner to memorise rules and to identify instances of rule violation. Subconscious acquisition is a very different process, facilitating the acquisition of rules at a subconscious level. According to Krashen (1982, 1988), when using the language to communicate meaning, the learner must draw on subconscious knowledge. The suggestion of conscious and subconscious processes functioning in language development was not new or radical; however, Krashen's assertion that these processes were totally separate, i.e. that learning could not become acquisition, was. Krashen went on to argue that the basic mechanism underlying language acquisition was comprehension. According to his comprehensible input hypothesis, when the student understands a message in the language containing a structure, his or her current level of competence advances by one step, and that structure is acquired. These hypotheses had a marked influence on practice, as outlined below.

• PROCESS-ORIENTED RESEARCH Research reviewed above focused on the products or outcomes of acquisition. A growing body of research considers learning processes, exploring the kinds of classroom tasks that appear to facilitate SLA. The bulk of this research focuses on activities or procedures which learners perform in relation to the input data. Given the extent of research in the field, this review is necessarily selective. In the first of a series of investigations into learner-learner interaction, Long (1981) found that two-way tasks (in which all students in a group discussion had unique information to contribute) stimulated significantly more modified interactions than one-way tasks (in which one member of the group possessed all the relevant information).

• Similarly, Doughty and Pica (1986) found that required information-exchange tasks generated significantly more modified interaction than tasks where exchange of information was optional. The term 'modified interaction' refers to instances during an interaction when the speaker alters the form in which his or her language is encoded to make it more comprehensible. Such modification may be prompted by lack of comprehension on the listener's part. (For further details, see Chapter 25 on task-based learning.) This research into modified interaction was strongly influenced by Krashen's hypothesis that comprehensible input was a necessary and sufficient condition for SLA, i.e. that acquisition would occur when learners understood messages in the target language. Long (1985a: 378) advanced the following arguments (which are paraphrased) in favour of tasks which promote conversational adjustments or interactional modifications on the part of the learner:

• Where (a) is linguistic/conversational adjustment, (b) is comprehensible input and (c) is acquisition: Step 1: show that (a) promotes (b). Step 2: show that (b) promotes (c). Step 3: deduce that (a) promotes (c). Satisfactory evidence of the (a) -> (b) -> (c) progression would allow the linguistic environment to be posited as an indirect causal variable in SLA. (The relationship would be indirect because of the intervening 'comprehension' variable.)

• In a relatively short period of time, SLA researchers have generated an impressive number of empirical studies. For detailed reviews of other studies and issues, see Larsen-Freeman and Long 1991; R.Ellis 1994.

Practice• In this section, practical pedagogical implications of the conceptual and

empirical work summarised above are presented and exemplified. I focus particularly on claims made by SLA researchers for product-oriented syllabuses, the implications of the comprehensible input hypothesis, and proposals for task-based language teaching. Krashen's work on the subconscious acquisition hypothesis and the comprehensible input hypothesis is summarised above. According to these hypotheses, innate processes guide SLA. In practical terms, researchers argued that learners should be provided with much natural input, especially extensive listening opportunities and particularly in the early stages of learning. They also argue that a silent phase at the beginning of language learning (when the student is not required to produce the new language) has proven useful for most students in reducing interlingual errors and enhancing pronunciation. Finally, and most controversially, they argued that formal grammar instruction was of limited utility as it fuelled conscious learning rather than subconscious acquisition (Dulay et al. 1982; Krashen and Terrell 1983). While relatively few researchers still subscribe to Krashen's hypotheses, at least in their original form, the value of rich and varied listening input early on has wide support (for more details, see Chapter 1).

• Krashen's comprehensible input hypothesis was challenged by Swain (1985), who investigated immersion programmes in Canada in which children receive content instruction in a language other than their LI. Native speakers of English receive instruction in maths, science, etc. in French, and vice versa for French native speakers. These children therefore receive massive amounts of comprehensible input. Despite this, L2 development is not as advanced as it should be according to the comprehensible input hypothesis. Swain found that the basic instructional pattern in class was one in which teachers talked a great deal and students got to say very little. Based on her observations, Swain formulated an alternative hypothesis - the 'comprehensible output' hypothesis - suggesting that opportunities to produce language were important for acquisition.

• The idea that grammatically sequenced syllabuses and the conscious learning of grammar were of limited utility in language learning was also vigorously rejected by proponents of the teachability hypothesis. In their view, grammatical structures can be classified according to the demands they make on the learner's working memory. The greater the demands, the more difficult the structure is to learn. An item will only be acquired, and therefore should only be taught, when the learner is developmentally ready to acquire it. The researchers who formulated this hypothesis argued that grammar could and should be taught, but that the timing of instruction should be in accord with the learner's developmental stage.

• The process-oriented research work of Long and others provided impetus for the development of task-based language teaching. In task-based language teaching, the start point for designing language courses is not an ordered list of linguistic items, but a collection of tasks. SLA research has informed the work of syllabus designers, methodologists and materials writers by suggesting that tasks encouraging learners to negotiate meaning are healthy for acquisition. The growing importance of 'task' as a fundamental element in curriculums and textbooks of all kinds underlines the growing links between process-oriented research and classroom pedagogy.

Current and future trends and directions

• Current SLA research orientations can be captured by a single word: complexity. Researchers have begun to realise that there are social and interpersonal as well as psychological dimensions to acquisition, that input and output are both important, that form and meaning are ultimately inseparable, and that acquisition is an organic rather than linear process. In a recent study, Martyn (1996) investigated the influence of certain task characteristics on the negotiation of meaning in small group work, looking at the following variables:– interaction relationship: whether one person holds all of the

information required to complete the task, whether each participant holds a portion of the information, or whether the information is shared;

– interaction requirement: whether or not the information must be shared;

– goal orientation: whether the task goal is convergent or divergent;– outcome options: whether there is only a single correct outcome, or

whether more than one outcome is possible.

• The results seem to indicate that while task variables appear to have an effect on the amount of negotiation for meaning, there appears to be an interaction between task variables, personality factors and interactional dynamic. This ongoing research underlines the complexity of the learning environment, and the difficulty of isolating psychological and linguistic factors from social and interpersonal ones. A major challenge for curriculum designers, materials writers and classroom practitioners who subscribe to task-based teaching is how to develop programmes that integrate tasks with form-focused instruction. This is particularly challenging when teaching beginners in foreign language contexts. A number of applied linguists (see, e.g., R. Ellis 1995) are currently exploring the extent to which one can implement task-based teaching with beginner learners, and experiments are under way to establish the appropriate balance and 'mix' between tasks which have non-linguistic outcomes and exercises which have linguistic outcomes.

• In searching for metaphors to reflect the complexity of the acquisition process, some researchers have argued that the adoption of an 'organic' perspective can greatly enrich our understanding of language acquisition and use. Without such a perspective, our understanding of other dimensions of language (such as the notion of 'grammaticality') will be piecemeal and incomplete, as will any attempt at understanding and interpreting utterances in isolation from the contexts in which they occur. The organic metaphor sees SLA more like growing a garden than building a wall.

• From such a perspective, learners do not learn one thing perfectly one item at a time, but learn numerous things simultaneously (and imperfectly). The linguistic flowers do not all appear at the same time, nor do they all grow at the same rate. Some even appear to wilt for a time before renewing their growth. Rate and speed of development are determined by a complex interplay of factors related to pedagogical interventions (Pica 1985); speech-processing constraints (Pienemann and Johnston 1987); acquisitional processes (Pienemann 1989); and the influence of the discoursal environment in which the items occur (Levinson 1983; McCarthy 1991; Nunan 1993, 1999).

Conclusion• In this chapter, I describe the emergence of SLA as a

discipline from early work in CA, error analysis and interlanguage development. I examine research into SLA in both naturalistic and instructional settings, considering both process- and product-oriented studies. The chapter also looks at the practical implications of current research for syllabus design and methodology, focusing in particular on the implications of SLA research for syllabus design, the input hypothesis, and task-based language teaching. The final part of the chapter suggests that future work will attempt to capture the complexity of the acquisition process by incorporating a wide range of linguistic, social, interpersonal and psycholinguistic variables into the design of the research process.

Key readings• R. Ellis (1994) The Study of Second Language

Acquisition• Krashen (1982) Principles and Practice in Second

Language Acquisition• Larsen-Freeman (1991) Second language acquisition

research: Staking out the territory• Larsen-Freeman and Long (1991) An Introduction to

Second Language Acquisition Research• Lightbrown and Spada (1993) How Languages are

Learned• Nunan (1999) Second Language Teaching and Learning