Language attrition: A matter of brain plasticity?

While it has long been assumed that brain plasticity declines significantly with growing maturity, recent studies in adult subjects show grey and white matter changes due to language learning that suggest high adaptability of brain structures even within short time-scales. It is not known yet whether other language development phenomena, such as attrition, may also be linked to structural changes in the brain. In behavioral and neurocognitive research on language attrition and crosslinguistic influence, findings suggest high plasticity as language interaction patterns of bilingual speakers change constantly and from early stages of language acquisition onwards. In this paper we will speculate on possible links between brain plasticity and L1 attrition in adult bilinguals, with particular attention to a number of factors that are put forward in memory frameworks in order to explain forgetting: time elapsed, frequency of L1 use, and interference from L2. In order to better understand the time-scales involved in the plastic changes during bilingual development, we then discuss some recent studies of re-exposure to L1 in formerly attrited immigrants, and their implications with respect to brain plasticity.

Adaptive functions of neurobehavioral plasticity in language learning and processing

This article presents a large scope of issues on early and late language plasticity that increase our understanding of the neurobehavioral dynamics of change, the main property of the learning brain. In their pioneering work, Bates and Kuhl have convincingly demonstrated that plasticity is intrinsic to development. Bates has provided new data on the impressive recovery of language in children with focal brain injury, highlighting that both hemispheres support the early phases of this change, contrary to previous assumptions. The fundamental reorganization of the early phonemic system around the age of 8 months proposed by Kuhl, combining neural commitment and social abilities, has powerful cascading effects for subsequent word learning. Our developmental crosslinguistic research on online sentence processing in monolinguals and simultaneous bilinguals has revealed distinctive linguistic patterns of “cue cost”, a multifactorial concept relevant for capturing the microplasticity of the processing system. Whatever the language, the shift around the age of 9 towards the canonical adult pattern indicates an efficient adaptive processing occurring with a small delay in bilinguals. Most salient, from childhood, bilinguals exhibit specific cue cost patterns with interactions. In older French adults, cue cost variability is mediated by processing speed which preserves online syntactic abilities but reveals plasticity limits in Alzheimer’s patients.

Capturing the variation in language experience to understand language processing and learning

A goal of early research on language processing was to characterize what is universal about language. Much of the past research focused on native speakers because the native language has been considered as providing privileged truths about acquisition, comprehension, and production. Populations or circumstances that deviated from these idealized norms were of interest but not regarded as essential to our understanding of language. In the past two decades, there has been a marked change in our understanding of how variation in language experience may inform the central and enduring questions about language. There is now evidence for significant plasticity in language learning beyond early childhood, and variation in language experience has been shown to influence both language learning and processing. In this paper, we feature what we take to be the most exciting recent new discoveries suggesting that variation in language experience provides a lens into the linguistic, cognitive, and neural mechanisms that enable language processing.

Parameter setting and acceleration

The present contribution analyzes the acquisition of subjects in French based on a longitudinal case study of a trilingual child aged 2;8–3;2 who acquired French, Italian and Spanish simultaneously. The three languages vary with respect to the null-subject property; French is traditionally characterized as a non-null-subject language, while Italian and Spanish are prototypical null-subject languages. Argument subject omissions in French are ungrammatical but frequently observed in monolingual children in early acquisitional phases, as are ungrammatical postverbal subjects which cluster with null-subjects. Bilingual children acquiring French produce fewer subject omissions and postverbal subjects. The present study also finds an acceleration effect in the trilingual child. The results are interpreted in light of a parameter setting which accounts for different verb classes at different locations with which the null-subjects occur, giving rise to ‘categorial CS’ or ‘congruent categorialization.’

Neuroplasticity of second language vocabulary acquisition

The present article reviews a series of selected functional and structural magnetic resonance imaging (MRI) studies focusing on the neuroplasticity of second language vocabulary acquisition as a function of linguistic experience. A clear-cut picture emerging from the review is that brain changes induced by second language vocabulary acquisition are observed at both functional and structural levels. Importantly, second language experience is even able to shape brain structures in short-term training of a few weeks. The evidence that linguistic experience can sculpt the brain in late second language learners, and even solely after a short-term laboratory training, constitutes a strong argument against theoretical approaches postulating that environmental factors are relatively unimportant for language development. Rather, combined neuroimaging data lend support to the determining role of linguistic experience in linguistic knowledge emergence during second language acquisition, at least at the lexical level.

Analyzing variability in L2 ultimate attainment

Ultimate attainment is typically more heterogeneous among second-language (L2) learners than among native speakers (e.g. Bley-Vroman, 1990). The present study offers a suite of simple analytical procedures aimed at exploring types and loci of variability in L2 attainment vis-à-vis those in the corresponding first language (L1), with special attention to certain learner-external factors that might condition such variabilities. To demonstrate the methods and their potential, we apply these procedures to learner and native acceptability judgment data published in Birdsong (1992). Under means analyses of item ratings and coefficients of variation (CV), a group of adult Anglophone learners of L2 French (ENS) are found to resemble native French controls (FNS). In contrast, under correlational analyses of ratings and CVs, ENS resemble FNS on grammatical items, but diverge on ungrammatical items. Correlational and means analyses of both CV and acceptability ratings reveal that ENS-FNS convergence is not predictable from the degree of FNS ratings variability, contra DeKeyser (2012). For both groups, we observe an interaction between FNS ratings variability and the grammatical status of items (ungrammatical vs. grammatical). Finally, for neither group do we find a relationship between the order of item presentation and ratings severity or CVs. We present our perspectives as a road map for future analyses of variabilities inherent in language learning outcomes.

The processing of passive sentences in German

This study examines the processing and interpretation of passive sentences in German-speaking seven-year-olds, ten-year-olds, and adults. This structure is often assumed to be particularly difficult to understand, and not yet fully mastered in primary school (Kemp, Bredel, & Reich, 2008), i.e. in children aged between six and eleven. Few studies provide empirical data concerning this age range; it is therefore unknown whether this assumption is warranted. Against this background, we tested whether the three age groups differed in their off-line comprehension of passive sentences. In addition, we employed Visual World eye-tracking to measure processing difficulties that may differ between age groups and may not be reflected in the final interpretations. Previous studies on adult language processing in German and English have documented a preference to interpret sentences according to an agent-first strategy. Our results show that all three groups make use of this strategy, and that all of them are able to revise this interpretation once the first cue indicating a passive sentence is encountered (the auxiliary verb form wurde). We conclude that at least from age seven on, children have the linguistic and cognitive prerequisites to process the passive morphosyntax of German and to revise initial sentence misinterpretations.