Age of second-language acquisition: Critical periods and social concerns

A classic topic in research on bilingualism across the lifespan is the relationship between the age at which learners start to acquire a second language (L2) and their ultimate level of proficiency in that language. Learning of an L2 that begins in infancy is typically associated with fluent speech, effortless language processing, and native accent. In contrast, late L2 learners tend to diverge from monolingual natives on measures of grammatical and lexical knowledge, processing speed, and acoustic properties of speech. Various classes of explanations for age effects in L2 acquisition – attitudinal, neurobiological, experiential, psycho-social, and cognitive – have been proposed in the literature. It is not the purpose of this chapter to examine these various accounts; for an overview, see Muñoz and Singleton (2011). Similarly, with the exception of a brief discussion in the section on social concerns, this chapter does not consider research on the efficiency of early foreign language teaching in schools; for an overview, see Lambelet and Berthele (2015). Rather, we are concerned with the hypothesis that L2 learning in naturalistic contexts is constrained by a critical period (CP). With its roots in the seminal works of Penfield and Roberts (1959) and Lenneberg (1967), the Critical Period Hypothesis for L2 acquisition (CPH/L2A) posits that nativelike attainment in the L2 from mere exposure is possible if learning begins within, but not after, a limited developmental span. Several recent overviews comprehensively summarize studies inspired by the CPH/L2A (references below), and we do not intend to rehash these surveys. Instead, we aim to provide readers with a technical toolkit to critically evaluate research on the divisive issue that is the CPH/L2A. To this end, we first discuss the CPH/L2A’s prediction that nativelikeness among learners with post-CP AoAs is impossible and highlight epistemological difficulties with this prediction. We then turn to the nature of the function that relates AoA to L2 attainment. The logic here is that a discontinuous function, but not a straight-line function, properly reflects the workings of a critical period. Here we illustrate how seemingly minor technical (statistical) caveats, which often risk being brushed under the rug as nit-picking, can fundamentally affect the conclusions of a study. In the final section, we expand our scope by considering the relevance of L2 acquisition theory to the social context of L2 learners and users. Specifically, we examine three issues relating to the notion that late L2 acquisition is inferior to L1 acquisition: early instruction of foreign languages in schools, the emphasis on deficits versus capacities, and societal prejudices against non-nativelikeness

La résolution de la liaison en français par des locuteurs natifs et non-natifs

Les processus de perception et de compréhension de la parole nécessitent la segmentation d’un signal acoustique continu où il y a souvent une absence de marques acoustiques explicites de frontière de mot ou de frontière de syllabe, à plus forte raison à l’intérieur des groupes rythmiques en français où se produisent les phénomènes de liaison et d’enchaînement. Considérons les cas où la resyllabation due à ces phénomènes crée une ambiguïté (par exemple, la séquence [œ̃.nɛʁ] correspond également à un air ou à un nerf). Cependant, des recherches récentes (Spinelli et al., 2003 ; Wauquier-Gravelines, 1996) ont mis en évidence des différences de durée entre les consonnes de liaison et les consonnes initiales. La tâche d’amorçage de Spinelli et al. suggère que ces variations peuvent fournir un indice acoustique dont les auditeurs se serviraient pour identifier des mots dans le flux sonore. Par exemple, le /n/ de un nerf serait plus long que celui de un air, ce qui produirait un effet d’amorçage qui favoriserait la reconnaissance de ‘nerf’ par rapport à ‘air’. En employant une tâche d’identification à choix obligatoire, notre étude vise à tester directement les capacités perceptives de locuteurs natifs du français et d’apprenants tardifs de français L2 dans les cas où la localisation des frontières est ambiguë. Les résultats suggèrent que, bien que ces variations de durée soient systématiquement présentes dans le signal acoustique, elles ne sont pas assez nettes pour permettre aux auditeurs de distinguer entre deux options. Même si les deux groupes de participants n’ont pas témoigné d’une sensibilité aux variations acoustiques, leurs réponses se sont avérées fortement similaires, ce qui suggère que les apprenants ont employé des stratégies perceptives comparables à celles des locuteurs natifs. On a donc pris en compte des facteurs relevant des processus du traitement descendant (top-down) tels que la fréquence lexicale et la plausibilité des phrases, mais aucun de ces facteurs ne s’est avéré jouer un rôle systématique dans les réponses.The online segmentation of the continuous speech stream requires that the listener employ strategies to identify word and syllable boundaries. In French, the phonological processes of liaison and enchaînement often render these boundaries ambiguous (consider un air ‘a melody’ and un nerf ‘a nerve’; both are syllabified as [œ̃.nɛʁ]). Some research on liaison (e.g. Spinelli et al., 2003; Wauquier-Gravelines, 1996) has suggested that speakers give listeners acoustic cues to word boundaries, and thus segmentation, through durational variation of pivotal consonants. Spinelli et al. suggest that priming of the word ‘nerf’ via un nerf versus via un air may be mediated by consonant length; a word-initial consonant (un Nerf) is longer than the corresponding consonant that surfaces in liaison (uN air). The current study more directly tested the perceptual capacities of speakers by employing a forced-choice identification task in which both native speakers of French and late learners of French as a second language were asked to differentiate ambiguous phonemic content. The results suggest that, though durational differences may be systematically present in the acoustic signal and may allow for the activation of vowel-initial candidates in the word recognition process, these durational differences are not robust enough to systematically guide listeners in disambiguation. Neither group performed above chance in the identification task; at the same time, the responses of the two groups were highly correlated. Factors involved in top-down processing such as frequency and plausibility were also taken into consideration, but these factors were found not to play a systematic role in the differentiation of ambiguous phonemic content

Focus, Vol. 1 No. 1

A literary magazine of student writing published by the Department of English of Stephen F. Austin State College.https://scholarworks.sfasu.edu/focus/1000/thumbnail.jp

Successful second language learning is tied to robust domain-general auditory processing and stable neural representation of sound

There is a great deal of individual variability in outcome in second language learning, the sources of which are still poorly understood. We hypothesized that individual differences in auditory processing may account for some variability in second language learning. We tested this hypothesis by examining psychoacoustic thresholds, auditory-motor temporal integration, and auditory neural encoding in adult native Polish speakers living in the UK. We found that precise English vowel perception and accurate English grammatical judgment were linked to lower psychoacoustic thresholds, better auditory-motor integration, and more consistent frequency-following responses to sound. Psychoacoustic thresholds and neural sound encoding explained independent variance in vowel perception, suggesting that they are dissociable indexes of sound processing. These results suggest that individual differences in second language acquisition success stem at least in part from domain-general difficulties with auditory perception, and that auditory training could help facilitate language learning in some individuals with specific auditory impairments

Plasticity, Variability and Age in Second Language Acquisition and Bilingualism

Much of what is known about the outcome of second language acquisition and bilingualism can be summarized in terms of inter-individual variability, plasticity and age. The present review looks at variability and plasticity with respect to their underlying sources, and at age as a modulating factor in variability and plasticity. In this context we consider critical period effects vs. bilingualism effects, early and late bilingualism, nativelike and non-nativelike L2 attainment, cognitive aging, individual differences in learning, and linguistic dominance in bilingualism. Non-uniformity is an inherent characteristic of both early and late bilingualism. This review shows how plasticity and age connect with biological and experiential sources of variability, and underscores the value of research that reveals and explains variability. In these ways the review suggests how plasticity, variability and age conspire to frame fundamental research issues in L2 acquisition and bilingualism, and provides points of reference for discussion of the present Frontiers in Psychology Research Topic