Freie Universität Berlin, Institute for English Language
Advanced Seminar 17363 „Second Language Acquisition“
Summer Term 2005, Fachsemester: 10

Age as a Factor in Second Language Acquisition

by: Jasmina Murad

Contents

1. Introduction  3

2. The Age Factor in Second Language Acquisition  5

2.1 The Critical Period Hypothesis 5
2.2 Evidence for and against the Critical Period Hypothesis in Second Language Acquisition  8

2.2.1 The ‘Younger = Better’ Position 8
2.2.2 The ‘Older = Better’ Position 14
2.2.3 The ‘Younger = Better in Some Respects’ Position  17
2.2.4 The ‘Younger = Better in the Long Run’ Position 19

3. Explanations for Age-Related Differences in Second Language Acquisition 23

4. Conclusion 25

5. Bibliography 30

1. Introduction

It is commonly known that children with regular faculties and given normal circumstances easily master their native language (L1). Unfortunately, perfect language mastery is rarely the result of second language acquisition (henceforth SLA). One of the central questions that SLA has tried to answer since its establishment as an independent field of study within applied linguistics is why learners of a non-native language (L2) evince such a high degree of interindividual variation in their final attainment relative to the L2 components and skills they have acquired. In order to offer a satisfactory response to this key issue, SLA researchers have posited the existence of a set of individual factors of a very different nature, such as aptitude, motivation, attitude, personality, and intelligence, among others, that might explain such variation. However, one of the most obvious potential explanations for the lack of success of L2 learners compared to L1 learners is that the acquisition of a foreign language begins at a later age than that of the mother tongue does (cf. Larsen-Freeman / Long: 153). Thus, it has been prevalently assumed that age itself is a predictor of second language proficiency. The influence of age is actually assessed to be not only significant but even decisive on the degree of L2 competence and performance attained (cf. Abello-Contesse et al.: 7).

If age indeed is a factor which determines upon the success in SLA – is there an optimal age to start learning a foreign language? It is often claimed that children are superior to adults, that is, that the younger the learner of a foreign language, the more effective the learning process and the better the outcome obtained. This assumption often derives from a distinctive element in the study of the age factor, the so-called critical period hypothesis (henceforth CPH), predicting that if the acquisition of a foreign language starts between the age of 2 and 12-13 (i.e., puberty), the process will be straightforward and the product will be complete (which is usually claimed to be the case in the acquisition of the L1), while individuals who begin their learning after this point – a kind of biological border – will find the process considerably difficult and the final outcome will be incomplete. Even though the CPH constitutes a strong and recurrent research line within the SLA, at the same time it is a changing and controversial area in practice since it tends to generate antagonistic positions among the SLA researchers. Thus, there exist also studies which dispute the assumption that children are superior to adults in learning a foreign language and maintain the exact contrary. Likewise, the explanations for the critical period as well as their empirical foundations have been questioned by different researchers (e.g., Krashen; Long). Is there indeed evidence for a critical period in SLA? Are there really age-related differences between young children, older children, and adults? And does the age of onset constitute a source of personal variation that is powerful enough to account for the varying levels of achievement that learners eventually reach? Since educators are interested in knowing what the best time is to start their instructions and how far older students can progress, the age factor is not only of great significance for SLA theory but also for language teaching practice. An important question which arises in this context is whether there is sufficient conceptual and empirical reason to justify making educational decisions on the basis of SLA research concerning the age factor. As is generally known, in Germany educational authorities decided to reduce the onset age of the first foreign language from the fifth to the third grade of elementary education. There are other countries as well which introduced the so-called “early start in L2 learning”¹. Does this reform, consisting primarily or exclusively in lowering the age of onset of L2 learning, conform to the results of the SLA studies on the age factor? This paper focuses on research which has been carried out on maturational constraints for SLA and hereby tries to find answers to the here posed questions.

2. The Age Factor in Second Language Acquisition

Few aspects in first language or second language learning have engendered more controversy than the age factor. Differences in interpretation are nothing new in any research area, of course. Here, however, disagreements as to both the facts and their explanation are very pronounced. The views range from the position that children are in all respects more efficient and effective second language learners than adults to the complete contrary position that adolescents and adults are more efficient and effective second language learners than children (cf. Singleton, 1995: 1f.). According to Singleton, at least four divergent opinions among the SLA researchers can be listed: In the first place, the ‘younger = better’ position, secondly, the straightforward counter-proposal, namely the ‘older = better’ position, thirdly, the ‘younger = better in some respects’ position, and fourthly, the ‘younger = better in the long run’ position. Among the wide range of studies, there is evidence relevant to each of the four positions on age-related differences in second language learning efficiency. In the course of this paper, several studies and opinions on the age factor in SLA will be presented and discussed². The further intention hereby is to ascertain whether one or more of the positions can be excluded and, if at all possible, whether one view can be assessed as the most evident or convincing.

2.1 The Crittical Period Hypothesis

The original formulation of the CPH is based upon the work of the German-born American neurologist Eric Lenneberg (1967). The hypothesis implies that children have a special innate propensity for acquiring language that is determined by biological factors – so to speak a biological clock that limits the period during which natural language acquisition can take place. This assumption is based on the biological observation that the brain of a child is plastic whereas the brain of an adult is rigid and set. According to Lenneberg, during early childhood language appears to be more spread out across both brain hemispheres, but as the child grows older and the two hemispheres become increasingly specialised for certain functions, language gradually relocates, settling in the left one. The CPH holds that primary language acquisition must occur during a critical period which starts at about the age of 2 years and ends at puberty (around the age of 12 or 13) with the establishment of lateralisation of the language function. Lenneberg argues that language acquisition before the age of 2 is impossible because the brain has not developed the capacities it needs. After puberty the natural acquisition of language is blocked because the brain has lost its cerebral plasticity. Of course, Lenneberg does not deny that language learning is possible after puberty. However, “automatic” acquisition from mere exposure to a second language seems to disappear: “Most individuals of average intelligence are able to learn an L2 after the beginning of their second decade, although the incidence of ‘language-learning blocks’ rapidly increases after puberty” (Lenneberg: 176). Moreover, he notes that foreign accents cannot be overcome easily after the end of the critical period. According to the neurosurgeon Penfield, an adult cannot learn a language as a child does because the adult learns through structures that have lost their flexibility. The child, on the other hand, can acquire one or more languages with ease because the corticothalamic speech mechanism in the child is still in the process of development (cf. Penfield / Roberts, 1959, in McLaughlin: 48).

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1 In Korea, the onset age was lowered from the seventh to the third grade beginning in 1997. In Spain, first foreign language teaching starts already in the first grade (since 2004).

2 Within the scope of this paper, I can merely present two to three studies in favour of each of the positions. Of course, there exists a good deal of further studies for the different views. Although not described in this paper (or at least not in detail), they will be taken into account when it comes to drawing conclusions.