Language mixing is a common feature of many bilingually-raised children's input. Yet how it is related to their language development remains an open question. The current study investigated mixed-language input indexed by observed (30-second segment) counts and proportions in day-long recordings as well as parent-reported scores, in relation to infant vocal activeness (i.e., volubility) when infants were 10 and 18 months old. Results suggested infants who received a higher score or proportion of mixed input in one-on-one social contexts were less voluble. However, within contexts involving language mixing, infants who heard more words were also the ones who produced more vocalizations. These divergent associations between mixed input and infant vocal development point for a need to better understand the causal factors that drive these associations.

Evidence from various empirical study types have converged to show bilingualism's potential for serving as a cognitive and brain reserves contributor. In this article, I contextualize, frame the need for and offer some expanding questions in this endeavor, inclusive of empirical pathways to address them. While the set of variables and questions discussed herein are definitively incomplete, they embody a good starting point for shaping future directions in research that considers the role bilingual language engagement can have for the developing mind and brain, inclusive of how various, non-linear factors impact the descent bilinguals of various types take down the proverbial mountain of life.

Titone and Tiv's Systems Theory of Bilingualism aims to “urge cognitive scientists and neuroscientists to better embrace sociolinguistic and sociocultural experiences as part of their theoretical and empirical purview”. No stronger case for such a framework can be found than in studies of developmental aspects of bilingualism. In fact, inclusion of sociocultural variation has been a common feature of many studies of dual language learning for some time, especially in studies of pre-school and early-school-age learners (see Genesee, 2019, for a review). Young dual language learners – neonates, infants and toddlers, exposed to more than one language – begin life as virtual tabula rasa and are capable of learning any language with facility. As a result, their language acquisition is necessarily tied to the sociocultural parameters of the learning environments they are exposed to. Moreover, as Titone and Tiv emphasize, the immediate and ultimate purpose of language learning is communication. Thus, young dual language learners must be attuned to and acquire the sociocultural constraints and norms for communicating effectively in more than one language. While sociocultural variation is important for understanding language acquisition even among monolingual children living in relatively homogeneous monocultural environments, sociocultural variation is inherent and, indeed, enhanced in the learning environments of children acquiring more than one language insofar as each language is intimately linked with different socio-cultural parameters. Sociocultural variation can be important for understanding bilingualism in yet another way. In studies of the neuro-cognitive consequences of bilingualism, it has been reported that there is a more pronounced association between dual language exposure and activation of certain brain areas among adolescent bilinguals from relatively low SES backgrounds than bilinguals from relatively high SES backgrounds (Brito & Noble, 2018). Inclusion of sociocultural variation in research on the effects of bilingualism can reveal a more nuanced view than emerges if such variation is not considered.

In their keynote paper, Dijkstra, Wahl, Buytenhuijs, van Halem, Al-jibouri, de Korte, and Rekké (2018) present a computational model of bilingual word recognition and translation, Multilink, that integrates and further refines the architecture and processing principles of two influential models of bilingual word processing: the Bilingual Activation Model (BIA/BIA+) and the Revised Hierarchical model (RHM). Unlike the earlier models, Multilink has been implemented as a computational model so its design principles and assumptions can be compared with human processing data in simulation studies – which is an important step forward in model development and refinement. But Multilink also leaves behind an important theoretical advancement that was touched upon in extending BIA to BIA+ (Dijkstra & Van Heuven, 2002): how linguistic context influences word processing. In their presentation of BIA+, Dijkstra and Van Heuven (2002) hypothesized that syntactic and semantic aspects of sentence context may affect the word identification system. Theoretically, this was an important step forward, as none of the bilingual word processing models (and few monolingual word processing models, for that matter) had incorporated linguistic context, and at that time only a handful of empirical studies had examined how linguistic context affects bilingual word processing. However, in the past 15 years a significant body of empirical work has been published that examines how semantic and syntactic information in sentences impacts word processing in bilinguals. These important insights are not incorporated in the Multilink model.

The present study asked whether oral vocabulary training can facilitate reading in a second language (L2). Fifty L2 speakers of English received oral training over three days on complex novel words, with predictable and unpredictable spellings, composed of novel stems and existing suffixes (i.e., vishing, vishes, vished). After training, participants read the novel word stems for the first time (i.e., trained and untrained), embedded in sentences, and their eye movements were monitored. The eye-tracking data revealed shorter looking times for trained than untrained stems, and for stems with predictable than unpredictable spellings. In contrast to monolingual speakers of English, the interaction between training and spelling predictability was not significant, suggesting that L2 speakers did not generate orthographic skeletons that were robust enough to affect their eye-movement behaviour when seeing the trained novel words for the first time in print.

Whereas growing evidence supports the advantages of bilingualism for brain structure and function, no study has shown multilingual-related neuroplasticity in response to speech stimuli at the subcortical level. To investigate the impact of multilingualism on subcortical auditory processing, the speech auditory evoked response (speech-ABR) was recorded on 35 young adults. The multilingual group completed the language experience and proficiency questionnaire (LEAP-Q). The results were that multilingual participants demonstrated evidence of enhanced neural timing processing, including a shorter wave D latency and the V-A duration, and a sharper V-A slope compared to the monolinguals in silence. In the noise condition, the speech-ABR measures degraded in most components, and no significant difference was observed between the two groups. The association between the total proficiency score and several subcortical responses was significant. This shows subcortical evidence of stronger neural synchronization in multilinguals relative to monolinguals, correlated with the self-report of multilingual experience.

Previous studies that contrasting bilinguals with monolinguals on Theory of Mind (ToM) have shown mixed results. We present a relatively large (N = 102) study comparing Polish–English sequential bilinguals living in the UK with Polish monolinguals living in Poland. Going beyond a simple group comparison, we explored the role of language proficiency and input in ToM abilities. A battery of eight tasks was used to measure ToM, and the groups were matched on age, gender, SES, IQ and L1 word comprehension. Although bilinguals did not differ from monolinguals in accuracy in ToM tasks, they demonstrated better reasoning abilities when providing justification for ToM responses. ToM accuracy scores were best predicted by L1 proficiency, but the justification scores were best predicted by both L1 and L2 proficiency. The findings suggest that the nuances of bilingual experience provide an important scaffolding context for ToM development.

The present study investigated the influence of lexical links and conceptual mediation in number word translation. In four experiments, a semantic blocking paradigm was used with numerical stimuli and stimuli from other non-number categories. The performance of Spanish L1–English L2 bilinguals was examined in backward and forward translation (Experiment 1 and 3), in naming Arabic digits and pictures (Experiment 2A) and in reading L1 and L2 words (Experiment 2B). The blocked context produced a facilitatory effect for numerical stimuli in the lower range. This result contrasts with the interference effect observed for stimuli from non-number categories in translation and naming tasks. These results are interpreted to mean that the translation of number words, particularly those in the lower range of the numeric sequence, takes place with a large influence of the lexical connections. It supports the suggestions that the influence of processing routes depends on the type of items.

Bilingualism: Language and Cognition (BLC) is now in its seventeenth year, and what started out as a new interdisciplinary journal dedicated to the study of bilingualism has now become the leading journal in its field. The first issue of BLC was published in 1998 with François Grosjean, Jürgen M. Meisel, Pieter Muysken and Judith Kroll as founding editors. Over the years, the editorship has passed to David Green, Ping Li and Carmen Silva-Corvalán, with Jürgen M. Meisel staying on. The journal has not merely survived for almost 17 years but has thrived, enjoying a steady increase in readership and submissions, suggesting that the interdisciplinary approach of the journal and the breadth of topics that it covers are hitting the mark. The 2013 impact factor mirrors this upsurge of interest: BLC's 2013 impact factor is quoted as 2.229, which makes it the 5th ranked out of 160 journals in linguistics and the 27th out of 83 experimental psychology journals. Hence it is a pleasure to report to the BLC readership that the journal is in excellent shape. This is primarily due to the outstanding dedication of the outgoing team of editors (Ping Li, David Green, Jürgen M. Meisel and Carmen Silva-Corvalán), to whom we would like to extend our gratitude. Under their tenure BLC has grown to be the leading journal in the field. We will continue to count on their advice.

Research among bilinguals suggests a foreign language effect for various tasks requiring a more systematic processing style. For instance, bilinguals seem less prone to heuristic reasoning when solving problem statements in their foreign (FL) as opposed to their native (NL) language. The present study aimed to determine whether such an effect might also be observed in the detection of semantic anomalies. Participants were presented NL and FL questions with and without anomalies while their eye movements were recorded. Overall, they failed to detect the anomaly in more than half of the trials. Furthermore, more illusions occurred for questions presented in the FL, indicating an FL disadvantage. Additionally, eye movement analyses suggested that reading patterns for anomalies are predominantly similar across languages. Our results therefore substantiate theories suggesting that FL use induces cognitive load, causing increased susceptibility to illusions due to partial semantic processing.

Bilinguals experience processing costs when comprehending code-switches, yet the magnitude of the cost fluctuates depending on numerous factors. We tested whether switch costs vary based on the frequency of different types of code-switches, as estimated from natural corpora of bilingual speech and text. Spanish–English bilinguals in the U.S. read single-language and code-switched sentences in a self-paced task. Sentence regions containing code-switches were read more slowly than single-language control regions, consistent with the idea that integrating a code-switch poses a processing challenge. Crucially, more frequent code-switches elicited significantly smaller costs both within and across most classes of switch types (e.g., within verb phrases and when comparing switches at verb-phrase and noun-phrase sites). The results suggest that, in addition to learning distributions of syntactic and semantic patterns, bilinguals develop finely tuned expectations about code-switching behavior – representing one reason why code-switching in naturalistic contexts may not be particularly costly.

To examine the combined effects of ageing and bilingualism in language processing, we tested young and older mono- and bilingual speakers in L1 comprehension and production. In Experiment 1, bilinguals were slower to detect words than monolinguals in sentences with a low-constraint context, but not when a high-constraint context was provided. Older adults tended to outperform younger adults in high-constraint sentences. In Experiment 2, older speakers were slower than younger speakers to produce small-scope prepositional phrases (e.g., ‘the cone above the grape), suggesting more extensive planning. Bilingual disadvantages were observed in larger-scope complex phrases (e.g., ‘the cone and the pink grape’). Individual differences in language proficiency did not modulate the effects. The results support bilingual disadvantages in syntactic processing and age-preserved syntax, alongside semantic processing unaffected by either bilingualism or age. We found no interactions between age and bilingualism, suggesting that these two factors independently impact language processing.

The purpose of the current report is to study the effects of language distance on noun and verb processing in bilingual speakers. We recruited two groups of bilingual speakers: one group spoke two typologically distant languages (Cantonese and English) and the other group spoke two typologically similar languages (Mandarin and Cantonese). Participants named object and action pictures in their first language. We controlled psycholinguistic properties of words such as frequency, AoA, imageability, name agreement, visual complexity, familiarity, and participants’ bilingual language experiences. Our findings revealed a significant role for language distance. We observed a difference between noun and verb processing in the similar language pair (Mandarin–Cantonese) due to interference induced by language similarity. However, in the distant language pair (Cantonese–English), the difference disappeared because of the lack of cross-language interference. Our findings support that current and future models of bilingual language processing should take into account the effects of language distance.

The article “A Dynamic Systems Theory approach to second language acquisition” by De Bot, Lowie and Verspoor discusses Dynamic Systems Theory (DST), and in particular the benefits of studying second language acquisition (SLA) within the DST framework. The article explains the main characteristics of DST, and goes on to show how various aspects of SLA can be treated from a DST perspective. In particular, the article proposes that the DST framework allows an investigation of how various social and cognitive aspects of SLA interact.

The Editors and members of the Editorial Board wish to thank the following guest consultants for having reviewed manuscripts submitted to the journal this past year.