This paper aims to foster discussion of the means by which bilinguals control their two language systems. It proposes an inhibitory control (IC) model that embodies the principle that there are multiple levels of control. In the model a language task schema (modulated by a higher level of control) “reactively” inhibits potential competitors for production at the lemma level by virtue of their language tags. The IC model is used to expand the explanation of the effect of category blocking in translation proposed by Kroll and Stewart (1994), and predictions of the model are tested against other data. Its relationship to other proposals and models is considered and future directions proposed.

The paper opens with an evaluation of the BIA model of bilingual word recognition in the light of recent empirical evidence. After pointing out problems and omissions, a new model, called the BIA+, is proposed. Structurally, this new model extends the old one by adding phonological and semantic lexical representations to the available orthographic ones, and assigns a different role to the so-called language nodes. Furthermore, it makes a distinction between the effects of non-linguistic context (such as instruction and stimulus list composition) and linguistic context (such as the semantic and syntactic effects of sentence context), based on a distinction between the word identification system itself and a task/decision system that regulates control. At the end of the paper, the generalizability of the BIA+ model to different tasks and modalities is discussed.

The present paper summarizes research showing that bilingualism affects linguistic and cognitive performance across the lifespan. The effect on linguistic performance is generally seen as a deficit in which bilingual children control a smaller vocabulary than their monolingual peers and bilingual adults perform more poorly on rapid lexical retrieval tasks. The effect on cognitive performance is to enhance executive functioning and to protect against the decline of executive control in aging. These effects interact to produce a complex pattern regarding the effect of bilingualism on memory performance. Memory tasks based primarily on verbal recall are performed more poorly by bilinguals but memory tasks based primarily on executive control are performed better by bilinguals. Speculations regarding the mechanism responsible for these effects are described.

In this article it is argued that language can be seen as a dynamic system, i.e. a set of variables that interact over time, and that language development can be seen as a dynamic process. Language development shows some of the core characteristics of dynamic systems: sensitive dependence on initial conditions, complete interconnectedness of subsystems, the emergence of attractor states in development over time and variation both in and among individuals. The application of tools and instruments developed for the study of dynamic systems in other disciplines calls for different approaches to research, which allow for the inclusion of both the social and the cognitive, and the interaction between systems. There is also a need for dense data bases on first and second language development to enhance our understanding of the fine-grained patterns of change over time. Dynamic Systems Theory is proposed as a candidate for an overall theory of language development.

Studies often report that bilingual participants possess a smaller vocabulary in the language of testing than monolinguals, especially in research with children. However, each study is based on a small sample so it is difficult to determine whether the vocabulary difference is due to sampling error. We report the results of an analysis of 1,738 children between 3 and 10 years old and demonstrate a consistent difference in receptive vocabulary between the two groups. Two preliminary analyses suggest that this difference does not change with different language pairs and is largely confined to words relevant to a home context rather than a school context.

Because the field of bilingualism is still relatively new, studies in the linguistics, psycholinguistics, language development and neurolinguistics of bilingualism have often produced conflicting results. It will be argued in this paper that some of the difficulties encountered by researchers could have been lessened, if not avoided, had close attention been paid to methodological and conceptual issues. Among the issues covered are bilingual participants, language mode, stimuli, tasks as well as models of bilingual representation and processing. Each issue is dealt with in the following way: first it is explained, then the problems it causes are discussed, and, finally, tentative solutions are proposed. Examples are taken from descriptive and experimental studies of normal bilingual adults and children as well as bilinguals suffering from aphasia and dementia.

Theoretical and empirical aspects of the neural bases of the mental lexicon and the mental grammar in first and second language (L1 and L2) are discussed. It is argued that in L1, the learning, representation, and processing of lexicon and grammar depend on two well-studied brain memory systems. According to the declarative/procedural model, lexical memory depends upon declarative memory, which is rooted in temporal lobe structures, and has been implicated in the learning and use of fact and event knowledge. Aspects of grammar are subserved by procedural memory, which is rooted in left frontal/basal-ganglia structures, and has been implicated in the acquisition and expression of motor and cognitive skills and habits. This view is supported by psycholinguistic and neurolinguistic evidence. In contrast, linguistic forms whose grammatical computation depends upon procedural memory in L1 are posited to be largely dependent upon declarative/lexical memory in L2. They may be either memorized or constructed by explicit rules learned in declarative memory. Thus in L2, such linguistic forms should be less dependent on procedural memory, and more dependent on declarative memory, than in L1. Moreover, this shift to declarative memory is expected to increase with increasing age of exposure to L2, and with less experience (practice) with the language, which is predicted to improve the learning of grammatical rules by procedural memory. A retrospective examination of lesion, neuroimaging, and electrophysiological studies investigating the neural bases of L2 is presented. It is argued that the data from these studies support the predictions of the declarative/procedural model.

Two eye-tracking experiments examined spoken language processing in Russian-English bilinguals. The proportion of looks to objects whose names were phonologically similar to the name of a target object in either the same language (within-language competition), the other language (between-language competition), or both languages at the same time (simultaneous competition) was compared to the proportion of looks in a control condition in which no objects overlapped phonologically with the target. Results support previous findings of parallel activation of lexical items within and between languages, but suggest that the magnitude of the between-language competition effect may vary across first and second languages and may be mediated by a number of factors such as stimuli, language background, and language mode.

Bilingual speech requires that the language of utterances be selected prior to articulation. Past research has debated whether the language of speaking can be determined in advance of speech planning and, if not, the level at which it is eventually selected. We argue that the reason that it has been difficult to come to an agreement about language selection is that there is not a single locus of selection. Rather, language selection depends on a set of factors that vary according to the experience of the bilinguals, the demands of the production task, and the degree of activity of the nontarget language. We demonstrate that it is possible to identify some conditions that restrict speech planning to one language alone and others that open the process to cross-language influences. We conclude that the presence of language nonselectivity at all levels of planning spoken utterances renders the system itself fundamentally nonselective.

Previous research has shown that bilingual children excel in tasks requiring inhibitory control to ignore a misleading perceptual cue. The present series of studies extends this finding by identifying the degree and type of inhibitory control for which bilingual children demonstrate this advantage. Study 1 replicated the earlier research by showing that bilingual children perform the Simon task more rapidly than monolinguals, but only on conditions in which the demands for inhibitory control were high. The next two studies compared performance on tasks that required inhibition of attention to a specific cue, like the Simon task, and inhibition of a habitual response, like the day–night Stroop task. In both studies, bilingual children maintained their advantage on tasks that require control of attention but showed no advantage on tasks that required inhibition of response. These results confine the bilingual advantage found previously to complex tasks requiring control over attention to competing cues (interference suppression) and not to tasks requiring control over competing responses (response inhibition).

This study investigated the possibility that lifelong bilingualism may lead to enhanced efficiency in the ability to shift between mental sets. We compared the performance of monolingual and fluent bilingual college students in a task-switching paradigm. Bilinguals incurred reduced switching costs in the task-switching paradigm when compared with monolinguals, suggesting that lifelong experience in switching between languages may contribute to increased efficiency in the ability to shift flexibly between mental sets. On the other hand, bilinguals did not differ from monolinguals in the differential cost of performing mixed-task as opposed to single-task blocks. Together, these results indicate that bilingual advantages in executive function most likely extend beyond inhibition of competing responses, and encompass flexible mental shifting as well.

Brysbaert and Duyck (this issue) suggest that it is time to abandon the Revised Hierarchical Model (Kroll and Stewart, 1994) in favor of connectionist models such as BIA+ (Dijkstra and Van Heuven, 2002) that more accurately account for the recent evidence on non-selective access in bilingual word recognition. In this brief response, we first review the history of the Revised Hierarchical Model (RHM), consider the set of issues that it was proposed to address and then evaluate the evidence that supports and fails to support the initial claims of the model. Although fifteen years of new research findings require a number of revisions to the RHM, we argue that the central issues to which the model was addressed, the way in which new lexical forms are mapped to meaning and the consequence of language learning history for lexical processing, cannot be accounted for solely within models of word recognition.

Many simultaneous bilinguals exhibit loss or incomplete acquisition of their heritage language under conditions of exposure and use of the majority language (Silva-Corvalán, 1994, 2003; Polinsky, 1997; Toribio, 2001; Montrul, 2002). Recent work within discourse-functional (Silva-Corvalán 1994) and generative perspectives (Sorace, 2000; Montrul; 2002; Tsimpli, Sorace, Heycock, Filaci and Bouba, 2003, in press) suggests that while syntax proper is impervious to language loss or attrition, syntax-related interfaces like lexical-semantics and discourse-pragmatics are not. This study investigates argument expression in adult simultaneous bilinguals who are heritage speakers of Spanish, because in this language subjects, direct, and indirect objects are regulated by syntactic, pragmatic and semantic factors. It was hypothesized that if language loss affects interface areas of competence more than the purely syntactic domains, then Spanish heritage speakers should display robust knowledge of null subjects as well as object clitics, but variable behavior in the pragmatic distribution of null vs. overt subjects, the a preposition with animate direct objects, and cases of semantically based dative clitic-doubling. Results of an oral production task administered to 24 intermediate and advanced heritage speakers and 20 monolinguals confirmed the hypotheses. With the erosion of pragmatic and semantic features, the grammars of the intermediate proficiency Spanish heritage speakers appear to display morphosyntactic convergence with English in the expression of subject and object arguments.

A word association experiment examined conceptual representation in bilingual memory. Dutch-English bilinguals associated twice to nouns and verbs that varied on concreteness and cognate status, once in the language of the stimuli (within-language), and once in the other language (between-language). Within- and between-language associations for concrete words and for cognates were more often translations of one another than those for abstract words and noncognates, and nouns evoked more translations than verbs. In both within- and between-language association, retrieving an associate was easier to concrete than to abstract words, to cognates than to noncognates, and to nouns than to verbs. These findings suggest that conceptual representation in bilingual memory depends on word-type and grammatical class: concrete translations, cognates, and noun translations more often share, or share larger parts of, a conceptual representation than abstract translations, noncognates, and verb translations. The results are discussed within the framework of distributed memory representation.

This paper has as its starting point the assumption that in acquiring two languages from birth, bilingual children separate their grammars from very early on. This does not, however, exclude cross-linguistic influence – the possible influence of one language on the other. The main focus of the paper is on the acquisition of syntax in a generative framework. We argue that cross-linguistic influence can occur if (1) an interface level between two modules of grammar is involved, and (2) the two languages overlap at the surface level. We show that both conditions hold for object drop, but not for root infinitives. Root infinitives satisfy the first condition: they involve the interface between syntax and pragmatics. However, they do not satisfy the second condition. Therefore, we expect cross-linguistic influence to occur only in the domain of object drop and not in the domain of root infinitives. Comparing the development of the two phenomena in a bilingual Dutch–French and a German–Italian child to the development in monolingual children, we show that this prediction is borne out by our data. Moreover, this confirms the hypothesis that cross-linguistic influence is due to language internal factors and not to language external factors such as language dominance: the periods during which we observe influence in the domain of object drop and non-influence in the domain of root infinitives are identical.

Two picture-word interference experiments were conducted to investigate whether or not words from a first and more dominant language are activated during lexical access in a foreign and less dominant language. Native speakers of Dutch were instructed to name pictures in their foreign language English. Our experiments show that the Dutch name of a picture is activated during initial stages of the process of lexical in English as a foreign language. We conclude that bilingual speakers cannot suppress activation from their first language while naming pictures in a foreign language. The implications for bilingual speech production theories are discussed.

Speaking more than one language demands a language control system that allows bilinguals to correctly use the intended language adjusting for possible interference from the non-target language. Understanding how the brain orchestrates the control of language has been a major focus of neuroimaging research on bilingualism and was central to our original neurocognitive language control model (Abutalebi & Green, 2007). We updated the network of language control (Green & Abutalebi, 2013) and here review the many new exciting findings based on functional and structural data that substantiate its core components. We discuss the language control network within the framework of the adaptive control hypothesis (Green & Abutalebi, 2013) that predicts adaptive changes specific to the control demands of the interactional contexts of language use. Adapting to such demands leads, we propose, to a neural reserve in the human brain.

In this paper we want to compare the results from monolingual children with object omissions in bilingual children who have acquired two languages simultaneously. Our longitudinal studies of bilingual Dutch–French, German–French, and German–Italian children show that the bilingual children behave like monolingual children regarding the type of object omissions in the Romance languages. They differ from monolingual children with respect to the extent to which object drop is used. At the same time, the children differentiate the two systems they are using. We want to claim that the difference between monolingual and bilingual children concerning object omissions in the Romance languages is due to crosslinguistic influence in bilingual children: the Germanic language influences the Romance language. Crosslinguistic influence occurs once a syntactic construction in language A allows for more than one grammatical analysis from the perspective of child grammar and language B contains positive evidence for one of these possible analyses. The bilingual child is not able to map the universal strategies onto language-specific rules as quickly as the monolinguals, since s/he is confronted with a much wider range of language-specific syntactic possibilities. One of the possibilities seems to be compatible with a universal strategy. We would like to argue for the existence of crosslinguistic influence, induced by the mapping of universal principles onto language-specific principles – in particular, pragmatic onto syntactic principles. This influence will be defined as mapping induced influence. We will account for the object omissions by postulating an empty discourse-connected PRO in pre-S position (Müller, Crysmann, and Kaiser, 1996; Hulk, 1997). Like monolingual children, bilingual children use this possibility until they show evidence of the C-system (the full clause) in its target form.

This study explores the extent to which bilingual speakers in stable bilingual communities become fully bilingual in their two community languages. Growing evidence shows that in bilingual communities in which one language is very dominant, acquisition of the dominant language may be quite unproblematic across sub-groups, while acquisition of the minority language can be hampered under conditions of reduced input. In Wales, children are exposed to both English and Welsh from an early age, either in the home or at school, or both. The data reported here indicate that regardless of home language background, speakers develop equivalent, mature command of English, but that command of Welsh is directly correlated with the level of input in Welsh in the home and at school. Furthermore, maintenance of Welsh in adulthood may be contingent on continued exposure to the language. The data have implications for theories of bilingual acquisition in stable versus immigrant bilingual communities, for optimal conditions for bringing up bilingual children, and for theories of critical periods of acquisition.

The relation between bilingualism and cognition is informative about the connection between language and mind. From the perspective of language, the question is how bilingualism might help or hinder cognition – narrowly interpreted here as executive function. From the perspective of higher cognition, the question is what kinds of experiences improve executive function. Reported cognitive benefits from bilingualism range from none to substantial as a function of age, type of bilingualism (e.g., life-long balanced vs later-onset or infrequent use of the other language), syntactic relation between the two languages, socio-economic and immigrant status, task, and laboratory. To understand the variability and inconsistencies in results with bilingualism, I analyze concepts of executive function and cognitive reserve and examine the range of factors (such as active video game playing, education, musical training, and aerobic exercise) that are known to correlate with or to improve executive function. I suggest that a) “executive function” is a complex set of cognitive processes, the components of which are sometimes minimally correlated with each other, depending on the task; b) bilingualism is inconsistently correlated with superior executive function and delayed onset of dementia; c) all speakers (mono- or bilingual) have non-linguistic ways of improving executive function; and d) benefits from bilingualism – and all cognitively challenging activities – are inconsistent because individuals vary in the number and kinds of experiences they have that promote superior executive function.