The Role of Language Switching During Cross-Talk Between Bilingual Language Control and Domain-General Conflict Monitoring.

The relationship between bilingual language control and executive control is debated. The present study investigated the effect of short-term language switching in a comprehension task on executive control performance in unbalanced bilinguals. Participants were required to perform a context task and an executive control task (i.e., flanker task) in sequence. A picture-word matching task created different language contexts in Experiment 1 (i.e., L1, L2, and dual-language contexts). By modifying the color-shape switching task, we created different contexts that do not involve language processing in Experiment 2 (i.e., color, shape, and dual context). Experiment 1 showed overall faster responses (in both congruent and incongruent trials) in the flanker task after a language switching context than after single (L1 or L2) contexts. This suggests that the language switching in a comprehension task affected general monitoring performance. By contrast, the nonlinguistic contexts in Experiment 2 did not affect flanker performance. This provides further evidence for the crucial role of language processing during switching to elicit short-term adaptions on domain-general conflict monitoring. Overall, our findings add to the previous studies by showing cross-talk between bilingual language control and domain-general conflict monitoring when language switching occurs in a comprehension task.

Am I truly monolingual? Exploring foreign language experiences in monolinguals.

Monolingualism has typically been understood as a homogeneous phenomenon. The linguistic experiences of monolinguals are usually overlooked when analysing the impact of foreign language experiences on language processing and cognitive functioning. In this study, we analyse the linguistic experiences of 962 English-speaking individuals from the United Kingdom (UK) who identified as monolinguals. Through an online survey, we found that more than 80% of these monolinguals had learned at least one foreign language, dialect, or type of jargon. More than half of this 80% of monolinguals also used languages they had learned at some point in their lives. Moreover, nearly 40% of all the studied monolinguals confirmed that they had been passively exposed to foreign languages or dialects in their environment; approximately a fourth of these monolinguals who declared exposure to at least one foreign language (or dialect) confirmed that they also used these languages. Furthermore, activities that involved passive use of languages (i.e., activities that require reading or listening but do not require speaking or writing; e.g., watching TV) were occasionally carried out in foreign languages: around 26% of these monolinguals confirmed the passive use of more than one language. Lastly, around 58% of monolinguals who had visited one or more non-English-speaking countries declared the active use of foreign languages during their stay(s). These results suggest that the linguistic experiences of monolinguals from the UK often include exposure to and use of foreign languages. Moreover, these results show the need to consider the specificity of the monolingual language experience when analysing the impact of foreign languages on cognitive functioning, as differences in the language experiences of bilinguals also have divergent impacts on cognition. Lastly, monolingual experiences are different from bilingual experiences; therefore, existing questionnaires that evaluate language experiences should be adapted to capture the particular linguistic experiences of monolinguals.

The source of attention modulations in bilingual language contexts.

Bilinguals who switch from a monolingual context to a bilingual context enhance their domain-general attentional system. But what drives the adaptation process and translates into the observed increased efficiency of the attentional system? To uncover the origin of the plasticity in a bilingual's language experience, we investigated whether switching between other types of categories also modulated domain-general attentional processes. We compared performance of Catalan-Spanish bilinguals across three experiments in which participants performed the Attentional Network Test in a mixed context and in two single contexts that were created by interleaving words with flankers. The contexts were related to switching (or not) between languages (Experiment-1) or between low-level perceptual color categories (Experiment-2) or between linguistic categories (Experiment-3). Both switching between languages and linguistic categories revealed increased target-P3 amplitudes in mixed contexts compared to single contexts. These findings can inform the Inhibitory Control model regarding the locus and domain-generality of attentional adaptations.

Structural brain changes with second language learning: A longitudinal voxel-based morphometry study.

The underlying mechanisms that adapt with L2 learning are still poorly understood. The present longitudinal study examined the effects of L2 learning on grey matter structure of Chinese college freshmen majoring in English. Participants were scanned twice, one year apart. Our voxel-based morphometry analyses revealed that gray matter volume (GMV) decreased in the left anterior cingulate cortex (ACC) and right inferior frontal gyrus (IFG) after L2 learning for one year. Critically, these structural adaptations correlated with changes in participants' language control ability across L2 learning. Moreover, age of acquisition of L2 was a significant predictor of volumetric change in the left ACC and L2 proficiency was a significant predictor of volumetric change in the right IFG. Overall, these findings enrich our understanding of the dynamic nature of structural brain adaptations, and the mechanisms these adaptations index, as a function of classroom L2 learning.

Rapid attentional adaptations due to language (monolingual vs bilingual) context.

Does our general attentional system adapt to the language context we are in? Bilinguals switch between contexts in which only one language is present or both languages are equiprobable. Previous research by Wu and Thierry (2013) suggested that the bilingual language context can modify the workings of inhibitory control mechanisms. Here we investigate whether this can be replicated and whether other attentional mechanisms (alerting and orienting) also adjust depending on whether we are in a bilingual or a monolingual situation. Bilinguals performed the Attentional Network Task (ANT) task, which allows us to measure three types of attentional processes: alerting, orienting and executive control. Crucially, while performing the ANT task, participants also saw words presented in only one language (e.g., Catalan; monolingual context) or in two languages (Catalan and Spanish; bilingual context); this allowed us to assess whether the three attentional processes would be modified by language context. Compared to the monolingual context, in the bilingual context the target-P3 amplitude was enhanced for the alerting and executive control networks but not for the orienting network. This suggests that bilinguals' state of alertness was enhanced when surrounded by words from two languages. Exploratory analyses reveal that within the bilingual context, language switches have an alerting effect, as indexed by a greater target-N1, thus impacting upcoming visual processing of the flanker. Response hand activation is speeded up for congruent trials in a similar way that arbitrary alerting cues speed them up. This speed-up was reflected in a greater LRP in the bilingual context, but it was not reflected in behavioral measures (RTs or ACC). Thus, a bilingual context can enhance attentional capacity towards non-linguistic information. It also reveals how flexible the cognitive system is.

Language control network adapts to second language learning: A longitudinal rs-fMRI study.

The current longitudinal resting-state functional magnetic resonance imaging study examined changes in language control network after one year of L2 English classroom learning. A group of Chinese college freshmen majoring in English underwent two scans, one before (i.e., Session 1) and one after (i.e., Session 2) the one-year L2 courses. Learners' language control abilities were assessed via a behavioral language switching task. Our graph theory and functional connectivity analyses revealed that with increased exposure to the L2, nodal betweenness in language control areas, such as the dorsal anterior cingulate cortex (dACC), decreased and connectivity between dACC and pre-supplementary motor area (pre-SMA) increased. Critically, these neural changes were correlated with participants' behavioral performance on the language switching task. Taken together, these findings suggest that the language control network in resting brain could be modulated by long-term L2 learning in a naturalistic classroom setting, and that the dACC/pre-SMA complex appears to play a critical role in language control.

The influence of contextual faces on bilingual language control.

How do faces with social-cultural identity affect bilingual language control? We approach this question by looking at the switch cost patterns and reversed language dominance effect, which are suggested to reflect bilingual language control mechanisms, in the absence (i.e., baseline context) or presence of faces with socio-cultural identity (Asian or Caucasian). In separate blocks, the face matched (i.e., congruent context) or mismatched (i.e., incongruent context) the language to be spoken. In addition, cue preparation time was manipulated to be long (Experiment 1) or short (Experiment 2). In both experiments, a unique asymmetric switch cost with larger costs for L2 was observed in the congruent context as compared with the baseline and incongruent contexts. Furthermore, the reversed language dominance effect was not modulated across contexts. These results suggest a critical role of contextual faces in modulating local but not global language control. Thus, bilingual language control changes flexibly within an environment that includes faces with socio-cultural identity.

Non-linguistic effects of language switching training.

What is the relationship between bilingual language control (BLC) mechanisms and domain-general executive control (EC) processes? Do these two domains share some of their mechanisms? Here, we take a novel approach to this question, investigating whether short-term language switching training improves non-linguistic task switching performance. Two groups of bilinguals were assigned to two different protocols; one group was trained in language switching (switching-task training group) another group was trained in blocked language picture naming (single-block training group). Both groups performed a non-linguistic and linguistic switching task before (pre-training) and after training (post-training). Non-linguistic and linguistic switch costs decreased to a greater extent for the switching-task training than for the single-block training group from pre- to post-training. In contrast, mixing costs showed similar reductions for both groups. This suggests short-term language switching training can transfer to the non-linguistic domain for certain sub-mechanisms (i.e., switch cost). Thus, there is some overlap of the control mechanisms across domains.

On the Reliability of Switching Costs Across Time and Domains.

Bilingual speakers are suggested to use control processes to avoid linguistic interference from the unintended language. It is debated whether these bilingual language control (BLC) processes are an instantiation of the more domain-general executive control (EC) processes. Previous studies inconsistently report correlations between measures of linguistic and non-linguistic control in bilinguals. In the present study, we investigate the extent to which there is cross-talk between these two domains of control for two switch costs, namely the n-1 shift cost and the n-2 repetition cost. Also, we address an important problem, namely the reliability of the measures used to investigate cross-talk. If the reliability of a measure is low, then these measures are ill-suited to test cross-talk between domains through correlations. We asked participants to perform both a linguistic- and non-linguistic switching task at two sessions about a week apart. The results show a dissociation between the two types of switch costs. Regarding test-retest reliability, we found a stronger reliability for the n-1 shift cost compared to the n-2 repetition cost within both domains as measured by correlations across sessions. This suggests the n-1 shift cost is more suitable to explore cross-talk of BLC and EC. Next, we do find cross-talk for the n-1 shift cost as demonstrated by a significant cross-domain correlation. This suggests that there are at least some shared processes in the linguistic and non-linguistic task.

Earlier and more distributed neural networks for bilinguals than monolinguals during switching.

The present study investigated processing differences between young adults who were English monolinguals or English-French bilinguals on a task- and language-switching paradigm. The mechanisms responsible for task switching and language switching were investigated using electrophysiological (EEG) measures. In nonverbal task switching, monolinguals and bilinguals demonstrated equivalent behavioral mixing (pure vs. repeat) and switching (repeat vs. switch) costs, but bilinguals were more accurate in the mixed blocks. Bilinguals used a more distributed neural network than monolinguals that captured the nonverbal mixing effect and showed earlier discrimination for the switching effect in the ERPs. In language switching, more distributed networks for bilinguals than monolinguals were found for the switching effect. The scalp distributions revealed more overlap between task switching and language switching for bilinguals than monolinguals. For switch costs, both groups showed P3/LPC modulations in both tasks, but bilinguals showed extended activation to central regions for both switching tasks. For mixing costs, both groups revealed modulations of the N2 but only bilinguals showed extended activation to the occipital region. Overall bilinguals revealed more overlapping processing between task- and language-switching than monolinguals, consistent with the interpretation of integration of verbal and nonverbal control networks during early visual processing for bilinguals and later executive processing for monolinguals.

Dutch-Cantonese Bilinguals Show Segmental Processing during Sinitic Language Production.

This study addressed the debate on the primacy of syllable vs. segment (i.e., phoneme) as a functional unit of phonological encoding in syllabic languages by investigating both behavioral and neural responses of Dutch-Cantonese (DC) bilinguals in a color-object picture naming task. Specifically, we investigated whether DC bilinguals exhibit the phonemic processing strategy, evident in monolingual Dutch speakers, during planning of their Cantonese speech production. Participants named the color of colored line-drawings in Cantonese faster when color and object matched in the first segment than when they were mismatched (e.g., , /laam4/ /lok3to4/, "blue camel;" , /hung4/ /lok3to4/, "red camel"). This is in contrast to previous studies in Sinitic languages that did not reveal such phoneme-only facilitation. Phonemic overlap also modulated the event-related potentials (ERPs) in the 125-175, 200-300, and 300-400 ms time windows, suggesting earlier ERP modulations than in previous studies with monolingual Sinitic speakers or unbalanced Sinitic-Germanic bilinguals. Conjointly, our results suggest that, while the syllable may be considered the primary unit of phonological encoding in Sinitic languages, the phoneme can serve as the primary unit of phonological encoding, both behaviorally and neurally, for DC bilinguals. The presence/absence of a segment onset effect in Sinitic languages may be related to the proficiency in the Germanic language of bilinguals.

Distinct morphological processing of recently learned compound words: An ERP study.

Our vocabulary is, at least in principle, infinite. We can create new words combining existing ones in meaningful ways to form new linguistic expressions. The present study investigated the morphological processing of novel compound words in overt speech production. Native speakers of Dutch learned a series of new compounds (e.g. appelgezicht, 'apple-face') that were later used as primes in a morphological priming task. In this protocol, primes were compound words morphologically related to a target's picture name (e.g. appelgezicht was used for a picture of an apple, Dutch appel). The novel primes were compared with corresponding familiar compounds sharing a free morpheme (e.g. appelmoes, 'applesauce') and with unrelated compounds. Participants were required to read aloud words and to name pictures in a long-lag design. Behavioral and event-related potentials (ERPs) data were collected in two sessions, separated by 48h. Clear facilitation of picture naming latencies was obtained when pictures were paired with morphological related words. Notably, our results show that novel compounds have a stronger priming effect than familiar compounds in both sessions, which is expressed in a marked reduction in target naming latencies and a decrease in the N400 amplitude. These results suggest that participants focused more on the separate constituents when reading novel primes than in the case of existing compounds.

Neural correlates reveal sub-lexical orthography and phonology during reading aloud: a review.

The sub-lexical conversion of graphemes-to-phonemes (GPC) during reading has been investigated extensively with behavioral measures, as well as event-related potentials (ERPs). Most research utilizes silent reading (e.g., lexical decision task) for which phonological activation is not a necessity. However, recent research employed reading aloud to capture sub-lexical GPC. The masked priming paradigm avoids strategic processing and is therefore well suitable for capturing sub-lexical processing instead of lexical effects. By employing ERPs, the on-line time course of sub-lexical GPC can be observed before the overt response. ERPs have revealed that besides phonological activation, as revealed by behavioral studies, there is also early orthographic activation. This review describes studies in one's native language, in one's second language, and in a cross-language situation. We discuss the implications the ERP results have on different (computational) models. First, the ERP results show that computational models should assume an early locus of the GPC. Second, cross-language studies reveal that the phonological representations from both languages of a bilingual become activated automatically and the phonology belonging to the context is selected rapidly. Therefore, it is important to extend the scope of computational models of reading (aloud) to multiple lexicons.

Second language phonology influences first language word naming.

The Masked Onset Priming Effect (MOPE) has been reported in speakers' first languages (L1). The aims of the present study are to investigate whether second language (L2) phonology is active during L1 reading, and to disentangle the contributions of orthography and phonology in reading aloud. To this end, Dutch-English bilinguals read aloud L1 target words primed by L2 words, while electroencephalography (EEG) was recorded. The onset of the primes was manipulated to disentangle the contributions of orthography and phonology (i.e. O+P+: kite - KUNST, 'art'; O+P-: knee - KUNST; O-P+: crime - KUNST; O-P-: mine - KUNST). Phonological but not orthographic overlap facilitated RTs. However, event-related brain potentials (ERPs) revealed both orthographic and phonological priming starting 125 ms after target presentation. Taken together, we gained insights into the time course of cross-linguistic priming and demonstrated that L2 phonology is activated rapidly in an L1 environment.

The role of orthography and phonology in English: an ERP study on first and second language reading aloud.

This study investigated the role of orthographic and phonological information in reading aloud. Dutch-English bilinguals (L2) and native English (L1) participants read aloud English words. The contribution of orthographic and phonological activation was distinguished with prime manipulation. Phonological overlap, but not orthographic overlap, facilitated the response latencies for both English L1 and L2 speakers. In contrast, event-related brain potentials also revealed orthographic priming for both groups. Altogether, the present results demonstrate that late L2 speakers exhibit a Masked Onset Priming Effect similar to that of native speakers. In addition, the ERP results revealed that orthographic information is activated earlier during reading, but is not detectable anymore at the behavioral response level when the task is reading aloud.

Reading aloud in Persian: ERP evidence for an early locus of the masked onset priming effect.

The current study investigates reading aloud words in Persian, a language that does not mark all its vowels in the script. Behaviorally, a masked onset priming effect (MOPE) was revealed for transparent words, with faster speech onset latencies in the phoneme-matching condition (i.e. phonological prime and target onset overlap; e.g. [symbol: see text] /sɒːl/; 'year' [symbol: see text] /sot/; 'voice') than the phoneme-mismatching condition (e.g. [symbol: see text] /tɒːb/ 'swing' - [symbol: see text] /sot/; 'voice'). For opaque target words (e.g. [symbol: see text] /solh/; 'peace'), no such effect was found. However, event-related potentials (ERPs) did reveal an amplitude difference between the two prime conditions in the 80-160 ms time window for transparent as well as opaque words. Only for the former, this effect continued into the 300-480 ms time window. This finding constrains the time course of the MOPE and suggests the simultaneous activation of both the non-lexical grapheme-to-phoneme and the lexical route in the dual-route cascaded (DRC) model.