Does complexity make multilingualism special? Since there is no unequivocal notion of complexity on which researchers agree, several characteristics that have been considered crucial for complexity are brought to bear on multilingualism. While multilingualism is fairly complex in some senses, for instance, because it requires that many variables…

Second language acquisition (SLA) research offers valuable insight on how languages are learned and how they coexist and influence each other. Sign language learners offer unique perspectives on SLA, allowing researchers to test theories that are otherwise constrained by access to only one modality. Current literature on sign language learning…

This article addresses different ways scholars conceptualize the multilingual repertoire. Formal and functional approaches investigate crosslinguistic influence across clearly demarcated languages, while dynamic systems theory and translanguaging approaches question countability and boundedness of languages. Problems with both perspectives are…

Using the lenses of bilingualism and social justice, I reflect on relevant conceptual and methodological issues encountered in the study of the linguistic development of heritage language speakers. Themes examined include the early but varying timing of heritage language learning; the surrounding linguistic environment, including the link between…

This article proposes basic (shared) and extended (nonshared) language cognition in native speakers as a function of two types of extralinguistic attributes: (a) degree of being multilingual and (b) variables related to amount and type of literacy experiences (e.g., level of education). This approach may throw new light on the question of whether…

I will propose a tentative framework of how words in two languages could be organized in the cerebral cortex based on neural assembly theory, according to which neurons that fire synchronously are bound into large-scale distributed functional units (assemblies), which represent a mental event as a whole ("gestalt"). For language this…

One of the most enduring questions in the field of bilingualism is whether bilingual infants and children initially have one language system or two. Research with adults indicates that, while bilinguals do not represent their languages in two fully encapsulated language systems, they are able to functionally differentiate their languages. This…

In bilinguals and second language learners, the native (L1) and nonnative (L2) languages coexist and interact. The L1 influences L2 production via forward transfer, as is seen with foreign accents. However, language transfer is bidirectional: even brief experience with an L2 can affect L1 production, via backward transfer. Here, we review the…

The goals of this article are to appraise second language acquisition's (SLA) disciplinary progress over the last 15 years and to reflect on transdisciplinary relevance as the field has completed 40 years of existence and moves forward into the 21st century. I first identify four trends that demonstrate vibrant disciplinary progress in SLA. I then…

In this article, I explore how connectionism might expand its role in second language acquisition (SLA) theory by showing how some symbolic models of bilingual and second language lexical memory can be reduced to a biologically realistic (i.e., neurally plausible) connectionist model. This integration or hybridization of the two models follows the…

Although research has consistently shown that a bilingual's two languages interact on multiple levels, it is also well-established that bilinguals can vary considerably in their proficiency in the second language (L2). In this paper we review empirical studies that have examined how differences in L2 proficiency modulate cross-language…

Distributional learning is a proposal for how infants might learn early speech sound categories from acoustic input before they know many words. When categories in the input differ greatly in relative frequency and overlap in acoustic space, research in bilingual development suggests that this affects the course of development. In the present…

Studies about bilingualism and second language acquisition (SLA) have a long tradition within linguistic and psycholinguistic research. The contributions from psycholinguistic research are crucial to the improvement of neurolinguistic models. This importance stems from the fact that psycholinguistic research is posing more specific questions than…

The incidence of nativelikeness in adult second language acquisition is a controversial issue in SLA research. Although some researchers claim that any learner, regardless of age of acquisition, can attain nativelike levels of second language (L2) proficiency, others hold that attainment of nativelike proficiency is, in principle, impossible. The…

Much of the research that contributes to understanding how bilingual children become literate is not able to isolate the contribution of bilingualism to the discussion of literacy acquisition for these children. This article begins by identifying three areas of research that are relevant to examining literacy acquisition in bilinguals, explaining…