In this article, the author addresses the question of how the mind represents two languages in simultaneous bilingualism. Some linguistic theories of intrasentential code switching are reviewed, with a focus on the Minimalist approach of MacSwan (1999b); the author concludes that evidence from code switching suggests that bilinguals have discrete and separate Lexicons for the languages they speak, each with its own internal principles of word formation, as well as separate phonological systems. However, the author argues that computational resources common to the two languages generate monolingual and bilingual syntactic derivations alike. Advantages of the Minimalist Program for the analysis of code switching data are discussed at some length.

We investigated the consequences of bilingualism for verbal fluency by comparing bilinguals to monolinguals, and dominant versus non-dominant-language fluency. In Experiment 1, bilinguals produced fewer correct responses, slower first response times and proportionally delayed retrieval, relative to monolinguals. In Experiment 2, similar results were obtained comparing the dominant to the non-dominant languages within bilinguals. Additionally, bilinguals produced significantly lower-frequency words and a greater proportion of cognate responses than monolinguals, and bilinguals produced more cross-language intrusion errors when speaking the non-dominant language, but almost no such intrusions when speaking the dominant language. These results support an analogy between bilingualism and dual-task effects (Rohrer et al., 1995), implying a role for between-language interference in explaining the bilingual fluency disadvantage, and suggest that bilingual fluency will be maximized under testing conditions that minimize such interference. More generally, the findings suggest a role for selection by competition in language production, and that such competition is more influential in relatively unconstrained production tasks.

This paper reports results from masked priming experiments investigating regular past-tense forms and deadjectival nominalizations with -ness and -ity in adult native (L1) speakers of English and in different groups of advanced adult second language (L2) learners of English. While the L1 group showed efficient priming for both inflected and derived word forms, the L2 learners demonstrated repetition-priming effects (like the L1 group), but no priming for inflected and reduced priming for derived word forms. We argue that this striking contrast between L1 and L2 processing supports the view that adult L2 learners rely more on lexical storage and less on combinatorial processing of morphologically complex words than native speakers.

Recent years have seen a surge in research comparing bilinguals to monolinguals, yet synthesizing this literature is complicated by the diversity of language and social backgrounds behind these dichotomous labels. The current study examines the labels and descriptions reported in 186 studies comparing bilinguals and monolinguals published between 2005–2015 in order to understand how bilingualism has been operationalized and to describe the degree to which different facets of bilingual experience are reported. Proficiency and usage were the most frequently reported features (77% and 79%), followed by language history (67%) and the language of schooling (60%). However, less than half of the studies measured proficiency objectively or reported proportional usage, and even less – 30% – described the sociolinguistic context from which the sample was drawn. Given the increase in language contact due to globalization, more transparent and comprehensive reporting of participant characteristics is critical to building our understanding of how bilingualism affects experience.

Functional neuroimaging, used in conjunction with experimental cognitive tasks, has been extremely successful in establishing functional specialization as a principle of brain organization in man. Positron emission tomography activation techniques and functional magnetic resonance imaging assess localized increases in cerebral blood flow associated with mental processes. The advent of these noninvasive neuroimaging techniques opened a “new era” in the investigation of language organization in healthy individuals. Neuroimaging studies of bilinguals and polyglots have highlighted the potential role of variables, such as age of acquisition, degree of proficiency, level of exposure, dominance/maternality on functional brain mapping of multiple languages. Consistent results indicate that attained proficiency, and maybe language exposure, are more important than the age of acquisition as a determinant of the cerebral representation of languages in bilinguals/polyglots. Indeed, increasing language proficiency appears to be associated at the neural level with the engagement of a common network within the dedicated language areas. Here we have reviewed the functional imaging literature on bilingualism.

Montrul's study is an important contribution to a recently emerged research approach to the study of bilingualism and languages in contact, characterized by its sound theoretical basis and its reliance on data from different – and traditionally non-integrated – domains of language development: bilingual first language acquisition (Müller and Hulk, 2001; Paradis and Navarro, 2003; Serratrice, 2004; Serratrice, Sorace and Paoli, in press), adult second language acquisition (Filiaci, 2003; Sorace, 2003), and native language attrition (Gurel, 2002; Tsimpli, Sorace, Heycock and Filiaci, in press). The generalization that is emerging from this approach is that interfaces between syntax and other cognitive systems (i.e. discourse pragmatics, lexical-semantics) exhibit more developmental instability than narrow syntax. For L1 attrition, which is the specific focus of the paper, this means that aspects of grammar at the syntax–discourse interface are more vulnerable to attrition than purely syntactic aspects. The identification of restrictions on the domain of occurrence of attrition is consistent with much previous descriptive research on this topic (e.g. Seliger and Vago, 1991). More recently, the same conclusion has been reached by a study on individual language attrition by Tsimpli et al. (in press), who investigated knowledge of the referential pronominal system in Greek and Italian in very advanced speakers of English. In this paper, Montrul tests the generalization on second-generation speakers of Spanish – or “heritage speakers” – a bilingual group that presents different characteristics from the adult L2 speakers investigated in Tsimpli et al.'s study. In addition to referential subjects, she also focuses on a different interface area of grammar – direct objects – that had not been investigated before. In these respects, Montrul's study is a welcome development. In other respects, however, the data are less than convincing and do not allow a straightforward interpretation. My commentary focuses on three fundamental questions raised not only by this study, but also by this type of research in general. The main focus will be the expression of referential subjects since this aspect of grammar has been investigated in other studies and therefore offers the possibility of direct comparison among results.

Bilingual reading can require more than knowing two languages. Learners must acquire also the writing conventions of their second language, which can differ in its deep mapping principles (writing system) and its visual configurations (script). We review ERP (event-related potential) and fMRI studies of both Chinese–English bilingualism and Chinese second language learning that bear on the system accommodation hypothesis: the neural networks acquired for one system must be modified to accommodate the demands of a new system. ERP bilingual studies demonstrate temporal indicators of the brain's experience with L1 and L2 and with the frequency of encounters of words in L2. ERP learning studies show that early visual processing differences between L1 and L2 diminish during a second term of study. fMRI studies of learning converge in finding that learners recruit bilateral occipital-temporal and also middle frontal areas when reading Chinese, similar to the pattern of native speakers and different from alphabetic reading. The evidence suggests an asymmetry: alphabetic readers have a neural network that accommodates the demands of Chinese by recruiting neural structures less needed for alphabetic reading. Chinese readers have a neural network that partly assimilates English into the Chinese system, especially in the visual stages of word identification.

The Revised Hierarchical Model (RHM) of bilingual language processing dominates current thinking on bilingual language processing. Recently, basic tenets of the model have been called into question. First, there is little evidence for separate lexicons. Second, there is little evidence for language selective access. Third, the inclusion of excitatory connections between translation equivalents at the lexical level is likely to impede word recognition. Fourth, the connections between L2 words and their meanings are stronger than proposed in RHM. And finally, there is good evidence to make a distinction between language-dependent and language-independent semantic features. It is argued that the Revised Hierarchical Model cannot easily be adapted to incorporate these challenges and that a more fruitful way forward is to start from existing computational models of monolingual language processing and see how they can be adapted for bilingual input and output, as has been done in the Bilingual Interactive Activation model.

Research on early bilingual development has suggested that syntactic transfer in bilingual acquisition is dependent on patterns of dominance and properties of the dual input the child is exposed to. In a case study of a Hong Kong bilingual child we present evidence of transfer from Cantonese to English in three areas where the two languages contrast typologically: wh-in-situ interrogatives, null objects and prenominal relatives are observed at a period when Cantonese is dominant as measured by MLUw. Comparisons with monolingual development show both qualitative and quantitative differences attributable to transfer. Language dominance is seen as the major determinant of transfer, with input ambiguity playing a role in the domain of null objects. While two distinct and separate linguistic systems are simultaneously developing in the bilingual mind, the pervasiveness of transfer implies a high degree of interaction between them. The findings show that the bilingual subject in our case study has taken a different path from monolinguals toward the target.

The goal of this study was to determine which linguistic aspects of second language speech are related to accent and which to comprehensibility. To address this goal, 19 different speech measures in the oral productions of 40 native French speakers of English were examined in relation to accent and comprehensibility, as rated by 60 novice raters and three experienced teachers. Results showed that both constructs were associated with many speech measures, but that accent was uniquely related to aspects of phonology, including rhythm and segmental and syllable structure accuracy, while comprehensibility was chiefly linked to grammatical accuracy and lexical richness.

This paper sketches a comprehensive framework for modeling and interpreting language contact phenomena, with speakers’ bilingual strategies in specific scenarios of language contact as its point of departure. Bilingual strategies are conditioned by social factors, processing constraints of speakers’ bilingual competence, and perceived language distance. In a number of domains of language contact studies important progress has been made, including Creole studies, code-switching, language development, linguistic borrowing, and areal convergence. Less attention has been paid to the links between these fields, so that results in one domain can be compared with those in another. These links are approached here from the perspective of speaker optimization strategies. Four strategies are proposed: maximize structural coherence of the first language (L1); maximize structural coherence of the second language (L2); match between L1 and L2 patterns where possible; and rely on universal principles of language processing. These strategies can be invoked to explain outcomes of language contact. Different outcomes correspond to different interactions of these strategies in bilingual speakers and their communities.

During speech comprehension, bilinguals co-activate both of their languages, resulting in cross-linguistic interaction at various levels of processing. This interaction has important consequences for both the structure of the language system and the mechanisms by which the system processes spoken language. Using computational modeling, we can examine how cross-linguistic interaction affects language processing in a controlled, simulated environment. Here we present a connectionist model of bilingual language processing, the Bilingual Language Interaction Network for Comprehension of Speech (BLINCS), wherein interconnected levels of processing are created using dynamic, self-organizing maps. BLINCS can account for a variety of psycholinguistic phenomena, including cross-linguistic interaction at and across multiple levels of processing, cognate facilitation effects, and audio-visual integration during speech comprehension. The model also provides a way to separate two languages without requiring a global language-identification system. We conclude that BLINCS serves as a promising new model of bilingual spoken language comprehension.

The main objective of this article is to provide new evidence regarding the impact of bilingualism on the attentional system. We approach this goal by assessing the effects of bilingualism on the executive and orienting networks of attention. In Experiment 1, we compared young bilingual and monolingual adults in a numerical version of the Stroop task, which allowed the assessment of the executive control network. We observed more efficient performance in the former group, which showed both reduced Stroop Interference and larger Stroop Facilitation Effects relative to the latter. Conversely, Experiment 2, conducted with a visual cueing task in order to assess the orienting network, revealed similar Cueing Facilitation and Inhibition (Inhibition of Return – IOR) Effects for both groups of speakers. The implications of the results of these two experiments for the origin and boundaries of the bilingual impact on the attentional system are discussed.

In an ongoing debate, bilingual research currently discusses whether bilingualism enhances non-linguistic executive control. The goal of this study was to investigate the influence of language-switching experience, rather than language proficiency, on this bilingual executive control advantage. We compared the performance of unbalanced bilinguals, balanced non-switching, and balanced switching bilinguals on two executive control tasks, i.e. a flanker and a Simon task. We found that the balanced switching bilinguals outperformed both other groups in terms of executive control performance, whereas the unbalanced and balanced non-switching bilinguals did not differ. These findings indicate that language-switching experience, rather than high second-language proficiency, is the key determinant of the bilingual advantage in cognitive control processes related to interference resolution.

This study investigated whether early especially efficient utilization of executive functioning in young bilinguals would transcend potential cultural benefits. To dissociate potential cultural effects from bilingualism, four-year-old U.S. Korean–English bilingual children were compared to three monolingual groups – English and Korean monolinguals in the U.S.A. and another Korean monolingual group, in Korea. Overall, bilinguals were most accurate and fastest among all groups. The bilingual advantage was stronger than that of culture in the speed of attention processing, inverse processing efficiency independent of possible speed-accuracy trade-offs, and the network of executive control for conflict resolution. A culture advantage favoring Korean monolinguals from Korea was found in accuracy but at the cost of longer response times.

During early stages of second language acquisition adult learners make frequent errors of lexical form. An experiment was performed to examine this effect in the laboratory. More and less fluent bilinguals in English and Spanish performed a translation recognition task in which they decided whether the second of two words was the correct translation of the first. In the critical conditions of the experiment the words were not correct translation equivalents, but related by lexical form (e.g., man-hambre (hunger) instead of man-hombre (man)) or by meaning (e.g., man-mujer (woman) instead of man-hombre (man)). Less fluent participants suffered more interference for form-related than for semantically related words relative to unrelated controls, but the reverse pattern held for more fluent participants. The results support a progression from reliance on word form to reliance on meaning with increasing proficiency in the second language. The performance of the more fluent bilinguals further suggests that the ability to retrieve semantic information directly for second-language words can potentially override some of the costs associated with lexical competition in languages that access shared lexical features.

This study investigated the role of domain-general inhibitory control in trilingual speech production. Taking an individual differences approach, we examined the relationship between performance on a non-linguistic measure of inhibitory control (the Simon task) and a multilingual language switching task for a group of fifty-six native English (L1) speakers learning French (L2) and Spanish (L3). Better inhibitory control was related to reduced switch costs, but only when switching into or out of the more dominant L1, where inhibitory control has been theorized to be most important (Green, 1998). The results provide evidence of a direct link between inhibitory control abilities and language switching capabilities, and suggest constraints on the conditions under which a domain-general inhibitory control mechanism supports language switching.

Lexically linked domains in language allow a speaker to formulate incompatible rules. How should they be represented theoretically? We argue that a speaker has a set of mini-grammars for different domains so that, in effect, every speaker is bilingual. It is argued that Tense or Agreement Checking, V-2 for quotation, and resumptive pronouns, all lead to bilingual representations. In addition, this perspective on Theoretical Bilingualism suggests that optionality and stages in the acquisition of an initial grammar should also be characterized as a form of bilingualism.

The obligatory use of the preposition a with animate, specific direct objects in Spanish (Juan conoce a María “Juan knows Maria”) is a well-known instance of Differential Object Marking (DOM; Torrego, 1998; Leonetti, 2004). Recent studies have documented the loss and/or incomplete acquisition of several grammatical features in Spanish heritage speakers (Silva-Corvalán, 1994; Montrul, 2002), including DOM (Montrul, 2004a). This study assesses the extent of incomplete knowledge of DOM in Spanish heritage speakers raised in the United States by comparing it with knowledge of DOM in fully competent native speakers. Experiment 1 examined whether omission of a affected grammatical competence, as measured by the linguistic behavior of 67 heritage speakers and 22 monolingual speakers in an oral production task and in a written acceptability judgment task. Experiment 2 followed up on the results of the acceptability judgment task with 13 monolingual speakers and 69 heritage speakers, and examined whether problems with DOM generalize to other instances of structural and inherent dative case, including ditransitive verbs and gustar-type psychological verbs. Results of the two experiments confirmed that heritage speakers' recognition and production of DOM is probabilistic, even for speakers with advanced proficiency in Spanish. This suggests that many heritage speakers' grammars may not actually instantiate inherent case. We argue that language loss under reduced input conditions in childhood is, in this case, like “going back to basics”: it leads to simplification of the grammar by letting go of the non-core options, while retaining the core functional structure.

Bilingual and multilingual individuals exhibit variation in everyday language experience. Studies on bilingualism account for individual differences with measures such as L2 age of acquisition, exposure, or language proficiency, but recent theoretical perspectives posit that the relative balance between the two or more languages throughout daily life (i.e., interactional context) is a crucial determinant for language representation, access, and control. We propose an innovative measure to characterize this construct by using entropy to estimate the social diversity of language use. Language entropy is computed from commonly-collected language history data and generalizes to multilingual communicative contexts. We show how language entropy relates to other indices of bilingual experience and that it predicts self-report L2 outcome measures over and above classic measures of language experience. Thus, we proffer language entropy as a means to characterize individual differences in bilingual (and multilingual) language experience related to the social diversity of language use.